Equitable urban green space planning for sustainable cities: a GIS-based analysis of spatial disparities and functional strategies

Abstract

Urban Green Spaces (UGS) are critical for fostering ecological sustainability and social equity in rapidly urbanizing cities like Islamabad, Pakistan. This study aimed to comprehensively map and classify Islamabad’s UGS, identify spatial disparities, and evaluate their ecological, recreational, and social functions. The research also proposed sustainable strategies for managing UGS to address urban challenges, including climate adaptation, biodiversity loss, and social inequity. The study developed a detailed spatial map of Islamabad’s UGS using Geographic Information Systems (GIS) and high-resolution satellite imagery. Seven typologies were categorized and analyzed, including parks, playgrounds, institutional green spaces, and waterways. Field surveys and random sampling validated the thematic maps, achieving an accuracy rate of 95.68% based on statistical metrics like Kappa coefficients. The study revealed significant disparities in UGS distribution. Wealthier zones had larger, well-maintained green spaces, while denser areas lacked accessible and functional UGS. Recreational spaces, institutional greenery, and waterways played a vital role in enhancing biodiversity, urban aesthetics, and community well-being, though many remain underutilized or degraded. Institutional green spaces contributed significantly to urban sustainability, comprising 17.05 km² of the total UGS area. The research highlights UGS as an essential Nature-Based Solution (NBS) for addressing urban challenges like heat islands, stormwater management, and social inequalities. The findings serve as a model for other rapidly urbanizing cities seeking ecological and social balance.

Introduction

Cities in the world are growing at an unprecedented rate, increasing the need for sustainable urban spaces¹. One of the most essential elements of creating such environments is the conservation and enhancement of urban green spaces (UGS). More than just aesthetic elements, UGS plays a crucial role in urban resilience. UGS refers to publicly accessible urban areas with vegetation that serve multiple functions, offering ecological, social, and economic benefits that enhance sustainability and livability. Green spaces help improve the air, manage flooding, capture carbon, and lower temperatures². Beyond environmental benefits, UGS also provides essential social value. Parks littered throughout cities can give them a space to hang out outside the house, but they cannot head toward cafes and restaurants. However, many rapidly growing cities around the globe, especially in the developing world like Pakistan, are putting enormous pressure on green spaces, which are disappearing or being overlooked in the face of urbanization and increased populations^1,3,4.

The capital of Pakistan, Islamabad, was planned to have big green areas for improving livability and sustainability^5,6,7. The city was designed in the 1960s to respond to this development city. Islamabad, with a population of over two million⁸ continues to exhibit green infrastructure as a defining feature. However, the quick expansion of the city has put pressure on these green areas. The green areas that used to be prominent have become poorly distributed, poorly maintained, or even left to neglect, particularly in the city’s eastern and southern regions^9,10,11. Unlike other areas, Islamabad’s wealthier neighborhoods, especially near the Margalla Hills, continue to maintain parks and open spaces.

These unequally distributed spaces in Islamabad are probably true of all other growing cities in the developing world. Rich places have many beautiful parks. Whereas poor places do not have many parks or green spaces¹². Islamabad is a well-planned city, but access to green spaces remains uneven. This begs the question: How can we ensure that all residents, rich and poor, close-in and far-flung, can reasonably access open spaces as the city grows?

One of the most significant difficulties in addressing this issue has been the availability of outdated and inaccurate information about the mapping, accessibility, and condition of UGS in Islamabad. The existing data is more often outdated or far too general, making it difficult for city planners to make informed decisions^13,14. Islamabad is not the only city facing the issue, as many cities in South Asia and outside face the same. Cities are developing rapidly, and traditional maps and planning tools do not keep up with this pace. There is a gap between urban planners’ goals and the force of the green infrastructure project. Geographic Information Systems (GIS) can make a difference here¹⁵.

As Islamabad expands, one of the biggest challenges is controlling the growth of green areas. If you do not have proper information on where green spaces are present and how they are being utilized, future development will become tough. In addition, green spaces in Islamabad are distributed unequally, as richer neighborhoods have more overall green spaces than denser ones. When this study was carried out, no GIS-based UGS mapping was done in Islamabad, so there is a high demand for better tools to inform decision-makers, policymakers, and urban planners.

This research hypothesized that there is an uneven distribution of UGS across Islamabad. Richer areas had bigger, more elaborate green spaces which were well-maintained. However, poorer or denser ones lacked these. Also, UGS, such as urban green belts, institutional green spaces, and playgrounds, were underused, whereas these spaces could significantly contribute towards urban sustainability transitions. This study thought ignoring these ignored areas would show their significance for sustainability. The study included qualitative observations of various themes, using interviews with the residents, officials, and planners to assess UGS accessibility and functionality. The available facilities heavily influence UGS’s social side, particularly concerning parks. These elements were essential in supporting the transition and promoting community participation, which is vital for long-term sustainability.

This study uses satellite imagery to provide a comprehensive, high-resolution GIS-based mapping of public green spaces in Islamabad. To better understand the city’s green infrastructure, UGS are classified into parks, gardens, playgrounds, forests, lakes, and institutional green spaces. The first phase focuses on mapping and classification, while the second phase evaluates their ecological and social functions. Furthermore, the third phase analyzes spatial variations across sectors to identify disparities in green space distribution and propose more equitable and sustainable urban planning strategies.

Research questions guided the study: What is the present situation of UGS in Islamabad? What are the differences in green spaces across Islamabad? These spaces serve the needs of those who use them, but how well-maintained are they? Could mapping tools help make decisions about managing urban green spaces? What measures can be taken to improve UGS distribution?

This study utilized GIS-based mapping to get a better insight into these questions. Researchers developed a base map with high-resolution satellite images of the city’s green spaces, which were then merged with land use, population density, and zoning information. The green spaces were classified according to their type and function. also, a field survey was carried out to validate the data so that the map accurately represented the real state of UGS on the ground. By doing a spatial analysis, we could spot divergent green space patterns, with some spaces having an excessive quantity while others lack it. The findings served as an essential grounding for recommendations on improving the city’s UGS management.

This investigation is both very much needed and vitally important. The data will be used to help city planners manage UGS. It will also help ensure equitable distribution of UGS to meet the needs of the growing population of Islamabad. In simpler terms, this research will help guide the actions of the city of Tbilisi in terms of how it manages its green spaces. The findings from this research can form a template for similar cities facing problems of balanced growth with sustainable development^16,17.

Measuring UGS is crucial for fostering sustainability transitions and shifting towards resilience and equity in urban systems. Urban data on the distribution, typology, and functionality of UGS enables planners to design strategies that mitigate ecological degradation, social inequity, and urban heat islands¹⁸. Cities like Islamabad experience unplanned urban development, which hampers their ability to meet sustainability goals due to the uneven distribution of green spaces.

UGS can be integrated into frameworks that prioritize their multifunctional benefits, including support for biodiversity, flood regulation, and social well-being, through quantification. This data-driven approach is the foundation of sustainability transitions that organize and maximize the potential of UGS¹⁹. This talks about GIS mapping and analysis of UGS in Islamabad to offer policy recommendations for sustainable urban development. It aims to give insights that can be useful for policymakers and planners to achieve sustainable urban development. Countries worldwide are becoming more urbanized, intensifying the need for well-planned green spaces to support sustainable development. This study presents a model focusing on equitable provisioning and optimizing urban green spaces. This study’s results will help Islamabad and cities worldwide as they face the obstacles of fast urbanization. In years to come, how we plan green spaces will determine the degree to which cities can be livable, resilient, and equitable.

Materials and methods

Study area

A planned urban center in Islamabad, Pakistan, was chosen for study. In terms of urban agglomeration, it is the 9th largest in the country. The city was established in 1960 as a modern, master-planned capital and officially replaced Karachi as Pakistan’s capital in 1963^5,20. In the middle of the Potohar Plateau, between 457 and 610 m above sea level, it lies beneath the Margalla Hills (Fig. 1). Since 1963, Islamabad’s population has grown from 0.117 million to 2.4 million and covers an area of 917.80 km^[221–23. As it falls under a humid subtropical climate (CWA in Köppen climate classification), the city experiences hot summers, monsoon seasons, and mild winters²⁴. The Islamabad Capital Territory is systematically organized into eight distinct zones: the Administrative Zone, Commercial District, Educational Sector, Industrial Sector, Diplomatic Enclave, Residential Areas, Rural Areas, and Green Area^21,23. The city of Islamabad is divided into five primary zones: Zone I, Zone II, Zone III, Zone IV, and Zone V, with Zone IV encompassing the most significant area (Table 1). Zone I primarily includes the fully developed residential sectors characterized by planned infrastructure and regulated development, making it an ideal case for studying urban green spaces. While Zone II comprises sectors still under development, each residential sector is denoted by an alphabetical letter combined with a numerical designation, covering approximately 2 km² each. For an in-depth study of urban green spaces, the focus is mainly on sectors within Zone I, known for their advanced development status and structured green space planning. These sectors include recently developed D-12 and surrounding rural and allocated areas, as well as E-7 to E-11, F-6 to F-11, G-4 to G-11, H-8 to H-12, and I-8 to I-12, among others (Fig. 1). Fatima Jinnah Park in sector F-9 exemplifies promising green spaces within these sectors, along with various green belts and parks dispersed throughout these areas. The selection of these sectors is designed to provide a comprehensive and representative overview of urban green space distribution and its influence on the quality of life in Islamabad. This approach ensures an in-depth evaluation of how green spaces contribute to urban sustainability, fulfilling both the recreational and ecological needs of the city’s residents.

Table 1 Zoning regulations and development characteristics of islamabad.

Islamabad has a humid subtropical climate characterized by hot summers, a distinct monsoon season, and mild winters (Fig. 2). The majority of rainfall occurs during the monsoon months, directly influencing vegetation growth and the sustainability of urban green spaces. These climatic conditions shape UGS planning by affecting species selection, maintenance strategies, and long-term ecological resilience.

Fig. 1

Geographic overview of the study area: (a) Islamabad’s location within South Asia, (b) zonal distribution of Islamabad, and (c) selected sectors for UGS study.

Fig. 2

Monthly mean temperature and precipitation variations in Islamabad.

Workflow of thematic mapping of UGS

All maps (Figs. 1, 4 and 5, and 6) were generated by the author using ArcGIS version 10.8 (Esri Inc., Redlands, CA, USA; https://www.esri.com/en-us/arcgis/about-arcgis/overview). Thematic mapping support data (Table 2; Fig. 3) was obtained and imported into ArcGIS 10.7.0.10. The soft copies of boundary data (Administrative, zonal, sectoral boundaries) were available (DWG extension). The extension file was imported into ArcGIS and converted from line format to polygon by using the “feature-to-polygon tool” available in the “Data Management Tools” of ArcGIS. Once the feature had been changed, it had to be projected into the projected coordinate system “WGS_1984_UTM_Zone_43N” using the “Project” feature in Data Management Tools. A hard copy of the land use map / sector-based planning map as a base reference data in GIS was scanned and georeferenced (Table 2).

Table 2 Data sources for thematic mapping.

Fig. 3

Methodological workflow for thematic mapping.

UGS typologies and classes for thematic mapping

The study employed the framework by Coles and Grayson²⁵ which emphasizes access and functionality to define urban green spaces (UGS). Consequently, only public green spaces characterized by vegetation and utilized for recreation or those enhancing the quality of urban life in Islamabad were included in the analysis. Despite their significance, private UGS were excluded due to their variable accessibility and potential for change. Based on usage functionality, the research categorized UGS into distinct typologies relevant to Islamabad’s context. Each typology was digitized, and their attributes were integrated as separate layers in the thematic map. This detailed classification of public UGS provides a comprehensive understanding of their diverse ecosystem functions and benefits, contributing to a holistic view of urban greenery in Islamabad (Table 3).

Table 3 USG typology, related land use class, and detailed description²⁵.

Georeferenced base imagery for digitization of UGS

Data from high-resolution Google Earth Imagery (GEI) is valuable, especially in urban areas where land cover patterns are complex mosaics of different land uses. GEI high resolution (2.5 m) was adopted as the base layer for identifying ground objects and allocating UGS typology land classes. Due to its open source, this data source is ideally suited for a thematic mapping approach involving manual classification (Fig. 3). The mosaic was produced in ArcGIS 10.7.1 using GE images captured using the software²⁶ on December 13, 2020, since no high-resolution images were publicly available. Shape2Earth plugin for MapWindow was used to georeference the JPEG images²⁷. The unregistered demo version worked perfectly since fewer than 500 GEI images existed. The current view in the GE window and a world file with WGS-84 coordinates are saved as part of the plugin. Based on the georeferenced GEI data, a single image was created in ArcGIS 10.7.1 using the geoprocessing tool, as shown in Fig. 4a. By implementing the “Mosaic” tool, the raster dataset was transformed into “GCS_WGS_1984” coordinates. The “Project” functionality of Data Management Tools converted this to WGS_1984_UTM_Zone_43N projected coordinates, as shown in Fig. 4b.

Fig. 4

(a) High-resolution raster image of Islamabad; (b) selected area for detailed thematic mapping of UGS.

The high-resolution GEI provided by satellite sensors allows for the mapping of UGS. Due to outdated imagery and overlay inaccuracies of the hard copy of the land use map, mapping UGS was challenging. By visual interpretation, UGS was vector-mapped in GIS using GEI as the base layer, and the polygons were assigned manually. Furthermore, a georeferenced land use plan, zone boundaries, buildings, and OSM road network data shapefile were added to the mapped layer.

Reference map accuracy and ground truth validation

A grid-based approach was utilized to sample the selected sectors of Islamabad randomly. A detailed graticule grid with 1-minute intervals for both parallels and meridians was created using ArcGIS, providing a systematic framework for sampling (Fig. 5). This grid generated a fishnet covering the study area’s extent, ensuring comprehensive spatial coverage. Random sampling points were then generated within this fishnet, providing a robust and unbiased sampling methodology²⁸. This approach facilitated the collection of spatially distributed samples²⁹ enabling a thorough analysis of the selected sectors in Islamabad (Fig. 5).

Overall, 301 ground truth GPS points representing UGS three typologies and seven classes were collected and added to ArcGIS as a shape file. The GPS points were retrieved from the Garmin (eTrex 30X) as track points and exported into ArcGIS as a shape file using GPS Trackmaker version 13.9. The distribution of ground truth points representing different classes is shown in Fig. 5. A base reference gridded map was utilized for random sampling.

Fig. 5

Map of ground-truth validation random sampling.

Accuracy and validity of UGS thematic mapping

Many factors affect the accuracy of a thematic map, including classification, mapping unit, and image quality³⁰. Accuracy measures how well the mapped attributes correspond to the reference dataset and is a key indicator of mapping reliability. Quantifying errors helps communicate the validity of results. Confusion (an error matrix) is commonly used for statistical accuracy analysis³¹. After incorporating the high-resolution georeferenced reference map from GEI and administrative boundary data from the CDA, the thematic map was converted into a raster format using the “feature to raster” tool. Rasters were generated from the classified polygons (vectors) of thematic maps 32 to ensure consistency. Raster values were then extracted and systematically compared with reference truth points using ArcGIS. The “frequency tool” was applied to calculate the occurrence of two values (truths and predictions), indicating the number of correct predictions. After constructing the confusion matrix using Eqs. (1)–(4), the kappa coefficient was computed using the pivot table tool to quantify classification accuracy and agreement.

$${\text{User's~accuracy~in~the~UGS~class~}}i = \frac{{n_{{ij}} }}{{n_{i} }}$$

(1)

$${\text{Producer's\,accuracy\,in\,the\,UGS\,class~}}i = \frac{{n_{{ij}} }}{{n_{i} }}$$

(2)

$${\text{Overall~}}\;{\text{accuracy}} = ~\frac{{\mathop \sum \nolimits_{{i = 1}}^{k} n_{{ii}} }}{n}$$

(3)

$${\text{Kappa}}\;~{\text{coefficient}} = ~\frac{{n\mathop \sum \nolimits_{{i = 1}}^{k} n_{{ij}} - \mathop \sum \nolimits_{{i = 1}}^{k} n_{i} n_{j} }}{{n^{2} - \mathop \sum \nolimits_{{i = 1}}^{k} n_{i} n_{j} }}$$

(4)

where k represents the number and the map nomenclature to be 1, 2,…, k; n_ij = number of Sample units in the map belonging to class i and in the reference belonging to class j; n_i. = sum of the elements in row i, i.e., the number of sample units classified into class i in the remotely sensed classification; n.j = sum of the elements in column j, i.e., the number of sample units classified into class j in the reference; n = total number of sample units.

Optimizing UGS based on small and large patches

This study analyzes and highlights small and large patches of UGS for targeted recommendations and optimization. Small patches are defined as those less than 0.1 km² (0.10000 km²), while larger patches exceed this threshold based on spatial distribution and functional significance. Using satellite imagery and GIS data, we created a histogram with custom bins to visualize the distribution of UGS. This analysis informs categorical recommendations to enhance the utility of UGS.

Results

Validity and reliability of the thematic mapping of UGS

As a result of our thematic map accuracy assessment, Table 4 presents a confusion matrix and the Kappa coefficient based on the raster map’s predictions (EqS. 1–4). In each row, the predicted values are represented by the raster map. In contrast, in each column, the reference data is presented. A diagonal entry in the matrix indicates the predicted value matches the reference value, while an off-diagonal entry indicates a mismatch. The recreational typology land use class “Parks and Gardens” is 97% accurate, with 56 correct predictions out of 58, whereas the “Playgrounds” class shows 48 correct predictions out of 50, giving a 96% accurate score. As a result of GPS points obtained through an on-site visit using a boat, the “Lakes” class obtained 100% accuracy, with all four instances predicted correctly.

In contrast, the “Waterway Green Spaces” and “Forests” classes are 96% and 94% accurate. Users’ accuracy for the “Institutions and Campuses” class is 93%, while the “Urban Green Belts” class is 98%. The producer’s accuracies also indicate a high level of reliability across most classes, with the “Lakes” class achieving 100% accuracy. Based on the sample size of 301 points, the thematic map was observed to be 95.68% accurate overall (Table 4). It indicates a very high level of agreement between predicted classifications and reference data, as measured by the Kappa coefficient, 94.61%. In this study, the thematic map accurately represents the spatial distribution of land cover classes and is reliable and valid. In addition to its high Kappa coefficient and overall accuracy, the classification model is effective at distinguishing classes, making it a useful tool for spatial analysis.

Table 4 The kappa coefficient of the thematic map was constructed using a confusion matrix.

Thematic categories and spatial analysis of UGS

In-depth thematic mapping of Islamabad’s UGS reveals its spatial distribution and classification. UGS categories are visualized in a comprehensive approach on the generated successive maps in Fig. 6a, b, c, d. Recreational UGS includes designated parks, gardens, playgrounds, lakes, waterways, green spaces, and forests. It enhances urban aesthetics and offers valuable recreational opportunities. Institutional UGS on government and educational campuses supports biodiversity and ecology. Providing recreation opportunities and improving air quality mitigates urban sprawl. As indicated by the spatial distribution, there are significant designated parks and gardens (12.45 km²), playgrounds (3.58 km²), lakes (6.26 km²), green spaces along waterways (4.99 km²), forests (2.38 km²), institutional campuses (17.05 km²), and green belts (9.82 km²). UGS is crucial in maintaining a sustainable urban environment and providing recreation, environmental, and aesthetic benefits for Islamabad residents through meticulous mapping and categorization. Besides improving urban life quality, this detailed analysis highlights the need to maintain and expand green spaces.

Fig. 6

Thematic mapping illustrating the successive layers of public urban green spaces (UGS): (a) Designated parks and gardens, including playgrounds and lakes; (b) forest buffer zones surrounding urban settlements specifically allocated as buffer zones; (c) institutional green spaces and water corridors following natural drainage lines; (d) green belts specifically allocated between planned sectors.

Recreational UGS—lakes

The lakes in Islamabad serve as significant recreational urban green spaces, providing ecological and social benefits. Prominent lakes such as Rawal Lake in the Margalla Hills National Park are developed with attached parks and gardens to fulfill recreational needs (Fig. 6a). These areas cater to a diverse population, offering activities such as boating, picnicking, and bird watching, thus enhancing the recreational landscape of the city. However, accessibility issues and maintenance challenges can limit their optimal use.

One of the notable water bodies in Islamabad is the Korang River, which originates from the Murree Hills and flows through Islamabad into the Rawal Lake. The Korang River plays a crucial role in the region’s hydrology, supplying water to Rawal Lake and providing drinking water to the residents of the twin cities (Rawalpindi and Islamabad). Despite its importance, the Korang River faces significant pollution challenges. Urban encroachments, industrial discharge, and untreated sewage have severely impacted the river’s water quality, posing environmental and health risks. Efforts to mitigate pollution include regulatory measures and public awareness campaigns, but enforcement remains inconsistent.

Other lakes and water bodies within the city also face underutilization due to urban congestion and environmental degradation. Despite efforts by local authorities to revitalize these water bodies, such as creating promenades and leisure areas, the provisions often remain underutilized due to poor maintenance and limited public engagement. Additionally, some lakes suffer from pollution and are used as dumping sites for sewage and garbage, detracting from their ecological and recreational potential.

Efforts to enhance the appeal and usability of Islamabad’s lakes include the development of better access points, regular maintenance, and public awareness campaigns to promote environmental stewardship. The potential of these lakes to serve as key urban green spaces can be fully realized through integrated management approaches that address ecological health and recreational infrastructure. The transformation of these lakes into vibrant public spaces would contribute significantly to the city’s sustainability and the well-being of its residents.

Recreational UGS—urban forest

Maintaining urban biodiversity and ecological balance in areas surrounding developed regions is essential, particularly in urbanized areas. These densely vegetated areas were purposely left undeveloped during city planning as buffer zones (Fig. 6b). Unlike the designated green belts and waterways green spaces, these regions remain pristine, undeveloped land that significantly contributes to the health and well-being of the city. Planning documents from the CDA reveal the strategic importance of these buffer zones in mitigating urban sprawl and preserving natural landscapes. During our field survey, we identified these densely vegetated areas in H-12, H-10, and the north-east side of the diplomatic enclave and classified them as urban forests. The vegetation in these areas is similar to that found in waterway green spaces and urban green belts, including native plants that thrive in undisturbed natural environments.

Institutional UGS—government and private institution

In an urban matrix, allocated space for institutions and a proportion of the green areas serve as critical ecological refuges. In addition to purifying air, they sequester carbon and regulate temperature. Additionally, green areas on educational campuses serve as living laboratories for environmental education. Thus, urban biodiversity is enhanced. These green spaces facilitate a deeper connection with nature and provide students and faculty with a natural setting for learning and relaxation. The aesthetic appeal of institutional buildings is also enhanced by maintaining grey and green structures (Fig. 6c). Ornamental and native plants improve urban sustainability and livability by supporting local biodiversity and mitigating the urban heat island effect. UGS management is essential to maximizing their ecological benefits.

Substantial areas have been allocated to public and private universities and institutions (Fig. 8), reflecting the commitment to education and research. The H-10 sector, designated for the International Islamic University, Islamabad (IIUI), spans a significant expanse and includes extensive green areas contributing to urban biodiversity and ecological balance. Similarly, the most sustainable campus in Pakistan and the world’s top-ranked (101–200 in Times Higher Education impact ranking), the National University of Sciences and Technology (NUST), occupies a large campus with well-maintained lawns and diverse plantings that support a variety of fauna. Similarly, Quaid-i-Azam University (QAU), with its sprawling campus set against the backdrop of the Margalla Hills, serves as a crucial ecological and educational hub. The Allama Iqbal Open University (AIOU) also covers a vast area, incorporating green spaces that enhance the urban environment. Beyond these major universities, numerous schools, colleges, and government departments are strategically situated throughout Islamabad, each contributing to the city’s green infrastructure (17.05 km²). These educational and governmental institutions foster learning and research and play a pivotal role in maintaining the city’s ecological resilience and sustainability by integrating substantial green spaces within their campuses.

Recreational UGS—designated parks and gardens

The provision and maintenance of parks and gardens within Islamabad’s planned residential sectors of Zone I are managed by the Capital Development Authority (CDA). As depicted in the figure, the parks and gardens vary significantly in size and layout across different sectors (Fig. 6a and Fig. 7a). These green spaces typically include amenities such as walking tracks, children’s play sections, gym areas, open lawns, and seating benches, with the level of maintenance differing from one sector to another. The frequency distribution graph based on the area (km²) indicates that smaller parks are more prevalent, predominantly located in residential neighborhoods (Fig. 6a). In contrast, larger parks, though fewer in number, are strategically placed to serve broader community needs across different sectors (Fig. 7 a. The provision of outdoor gym equipment is a recent addition and is widely used; however, in some places, the position is random. As very few parks have more area (Fig. 6a), such as F-9 Park, Lake View Park, Japanese Children Park, Rose and Jasmine Garden, and Kachnar Park, are added with more facilities.

The qualitative survey reveals that park accessibility in Islamabad varies based on gender, age group, designated hours, and proximity to residential areas, as reported by community members and stakeholders. Small parks with limited facilities within residential localities were found to be generally accessible to the public and heavily influenced by community involvement in maintaining and providing facilities. The CDA, cleanliness, and maintenance are only subject to the participation of locals; no regular services of such activities are provided; in many sectors (I and G series), nominated groups of residents manage these parks, address facility issues, and oversee maintenance with the help of the CDA. Conversely, large parks are directly managed by the CDA and maintained by designated staff. Additionally, some parks are adopted by third parties for development and maintenance, ensuring higher standards of care and facility management. Most large Parks charge nominal fees for the entrance and parking areas and the recreational facilities owned by the private sector.

A detailed qualitative survey revealed that parks and gardens have significantly enhanced residents’ quality of life, highlighting their role in social interaction, mental well-being, and recreation of Islamabad by providing ecological services. Undoubtedly, parks and gardens have played a pivotal role in this improvement. Indigenous plants such as Neem (Azadirachta indica), Amaltas (Cassia fistula), and Chir pines (Pinus roxburghii) are found very common, along with seasonal shrubs to enhance recreation like Jasmine (Jasminum officinale) and Hibiscus (Hibiscus rosa-sinensis), which contribute to carbon dioxide sequestration (Supplementary Table I). These parks and gardens also maintain ecological balance by providing bird and insect habitats while offering water management services that mitigate climate-related impacts. Strategically planned, most parks and gardens effectively reduce surface runoff, recharge groundwater, and prevent soil erosion. Moreover, parks regulate urban microclimates, lowering ambient temperatures and creating comfortable outdoor spaces, counteracting the urban heat island effect. Beyond their environmental benefits, parks positively influence mental and physical health. By promoting physical activity, reducing stress, and offering natural recreational opportunities, green spaces contribute to climate adaptation.

Recreational UGS—waterways green spaces

A vital component of Islamabad’s green infrastructure is left along natural drainage lines, such as Nullah Lai. The plant communities in these areas are distinct due to soil properties and human activities and feature a variety of native and invasive species³³. Higher moisture content areas tend to support native species like Populus euphratica and herbaceous plants, while disturbed sites tend to support invasive species like Broussonetia papyrifera (Supplementary Table 2). These green spaces provide wildlife habitat in urban ecosystems, increasing ecological resilience. Our close observations indicate that these areas are often underutilized due to poor maintenance and public awareness despite their environmental importance. It is essential to preserve native species, control invasive species like Broussonetia papyrifera, and monitor soil properties. Green spaces can be fully realized if they are accessible and sustainable. There are distinct distributions of small and large patches, covering an area of 4.99 km²; the majority are relatively small (0.1 km²) (Fig. 7c). Despite their small size, these patches contribute significantly to urban biodiversity, flood mitigation, and other ecosystem services. Despite their smaller numbers, larger patches play a significant role in urban ecological resilience and provide greater recreational opportunities and habitat. Islamabad’s environmental health and sustainability depend on the conservation and enhancement of waterway green spaces, both small and large.

Fig. 7

Area-wise frequency distribution of (a) parks, (b) playgrounds, and (c) waterways green spaces in Islamabad.

Recreational UGS—playground

The study revealed a diverse range of recreational UGS, primarily focused on sports facilities, across selected sectors in Islamabad (Fig. 7b). While many sectors provided football and cricket grounds, contributing to urban heat mitigation and ecosystem services, the distribution of other sports facilities was uneven (Fig. 8). Tennis and basketball courts were present in some sectors, promoting physical activity and social cohesion. Specialized facilities like karting, paintballing, and skating were limited and often required extensive travel. A significant gap was identified in providing gender-specific playgrounds and facilities, with most catering to young males. Additionally, many public spaces were overcrowded due to a lack of designated sports areas, and existing facilities often suffered from poor maintenance, inadequate safety measures, and limited vegetation. The study also highlighted the challenges of managing and maintaining recreational UGS, with varying public and private involvement levels.

Fig. 8

Area-wise frequency distribution of institutional green spaces across the selected sectors of Islamabad.

Green belts— urban green belts

The green belts in Islamabad were strategically included in the Master Plan to act as buffers between different urban sectors, preserving aesthetic appeal and maintaining ecological balance (Fig. 6d). Field observations indicate that, despite their ecological significance, these green belts face challenges from infrastructure development and informal settlements. Encroachment from road construction and other development projects has reduced their size and functionality. Regular maintenance, preservation of native species, control of invasive species, and monitoring of soil properties are essential to sustain the ecological functions of these green belts³³. Their strategic placement and diverse vegetation make them indispensable components of the city’s green infrastructure, significantly contributing to the environmental health and sustainability of Islamabad. The concept of using green belts to prevent the merging of rural and urban areas dates back to World War II³⁴. The reasons for implementing green belts around cities varied: in England, they were used to stop urban expansion, while in Jerusalem, they served political purposes³⁵. In Islamabad, green belts serve a unique purpose. According to the Master Plan of Islamabad, green belts were incorporated along every service road and highway. These green belts were intended for future road expansions and to act as barriers, separating residential areas from the roads. Thematic observations reveal that these green belts are underutilized, highlighting the need for better management and utilization strategies to maximize their ecological and social benefits.

The graph illustrates the distribution of green belt areas in Islamabad, highlighting their frequency of occurrence across different size categories. This study identifies the area of current green belts (9.82 km²) (Fig. 9). Most green belts are relatively small, with the highest frequency observed in areas less than 0.1 km².

Fig. 9

Distribution of Green Belt Areas highlighting the prevalence of small green spaces within the urban landscape.

Thematic quantification of UGS

Distribution and sizes of different Urban Green Space (UGS) types were qualified based on thematic observation and mapping (Fig. 10). The Urban Green Belts and Institutional UGS categories dominate, with total areas of 19.64 km² and 17.05 km², respectively. Recreational Parks and Gardens also hold significant space at 12.45 km². The mean area values indicate the average size of individual spaces, while the maximum values show the largest spaces within each type. Figure 10 complements this by showing the proportional distribution of each UGS type, with urban green belts (UBG) and institutional green spaces (IGS) making up over half of the total UGS area, highlighting their importance in urban planning and sustainability. This combined analysis underscores the focus on extensive green belts and institutional spaces while noting the substantial role of recreational parks.

Fig. 10

Analysis of UGS types: total area, mean, maximum values, and proportional distribution.

Discussion

It’s vital to quantify UGS to understand how these spaces are distributed in space and how accessible they are. According to earlier studies, the results exemplify that the spatial mapping of UGS sites using GIS and remote sensing tools provides helpful information for urban planning and sustainability. Similar to^36,37 , the spatial analysis of UGS may help policymakers assess the availability of green space and help indicate potential gaps in access to it, particularly in rapidly urbanizing areas.

The study findings indicate a significant spatial distribution of UGS in Islamabad, consistent with the urban core-periphery model. It is concentrated in low-density urban settings and is rare in high-density urban settings. The same distribution pattern is observed in other metropolitan areas⁹. Urban densification generally reduces green space in the center area. As a result, accessibility to urban residents is unevenly distributed and more concentrated in satellite cities.

Quantifying UGS, as exhibited in this research, is a vital step toward implementing sustainability transitions at the urban level. Understanding variations in green spaces can help urban planners take adequate measures to boost a city’s effectiveness. This study’s results show that the disparities in UGS availability reflect socio-environmental inequalities in developing cities. Working on these inequalities is essential to facilitating an equitable transition towards sustainability.

Insights from data-driven UGS quantification can capture urban policies that support sustainability transitions, namely ecological, social, and climate. For example, the integration of UGS into zoning policies or development plans to increase their potential as Nature-Based Solutions (NBS) can help address urban flooding and air pollution while improving residents’ quality of life¹⁸. This study shows how quantification can connect planning and sustainability by ensuring that UGS delivers long-term environmental and social benefits.

Such spatial analysis of UGS has amply proven its significance in enhancing the quality of air, controlling temperature, and managing stormwater. These green spaces help reduce urban heat islands and air pollution, according to^38,39. Prioritizing trees in UGS with aboveground biomass will help in carbon sequestration and the absorption of pollutants. This is particularly important in urban areas with high vehicular emissions. Yet, while the study distinguished the ecological benefits of UGS, it also found obstacles to optimizing these services due to uneven spatial distribution. The environmental contribution and ecological effectiveness will be much less with fewer well-planned areas. This observation is supported by⁴⁰who affirm that the ecological value of UGS may be ruined due to a lack of spatial planning and other built environments.

Besides helping nature, UGS offers critical social benefits that improve communities, encourage play, and promote mental wellness. The research revealed that Islamabad’s UGS encourages various recreational activities that can renew our commitment to physical activity. These benefits are widely noted in urban studies because easy access to them improves mental health, reduces stress, and increases physical activity^41,42. This is especially true for urban places like Islamabad, where the city does not allow its inhabitants access to any natural landscape, thus making the UGS necessary for continuing social and mental well-being. Even with all these benefits, it became apparent that the lack of green space limits residents’ use of UGS in high-density areas. According to studies, the unequal distribution of green spaces contributes to social inequalities, given that residents of low-density, suburban areas generally have much better access to high-quality green spaces than those who live in central, high-density areas^43,44. Different urban planners and owners must ensure equal UGS in residential buildings to benefit everyone and fix these inequalities.

UGS provides value by improving the value of properties, improving tourism, and reducing health costs. The research shows that the proximity of green spaces to a property does affect the prices in Islamabad. This is also supported by properties near well-looked-after green spaces, which tend to be more valued. This value reflects the wider economic benefits UGS provide^45,46 . We ought to ensure UGS’s sustainable funding and maintenance by looking into indirect economic benefits like healthcare savings resulting from better lifestyles. Yet, most residents do not recognize these benefits and use UGS primarily for recreational and aesthetic purposes rather than for economic gain. Making people more knowledgeable about UGS’s long-term contribution will help the community become more supportive of their investment in green infrastructure, which is especially important in urban areas where financial resources for maintenance are limited⁴⁷.

Even if the UGS systems have multiple ecological, social, and economic benefits, their maintenance and sustainability pose an ongoing challenge. It is mainly because of their presence in densely populated urban areas. According to this study, the under-maintenance and overcrowding negatively affect the UGS in Islamabad. Similar conclusions were drawn by ^37,8 that dysfunctionality and inoperability occur if green spaces are poorly maintained. For UGSs to be safe, accessible, and ecologically productive, a regular maintenance regime, including litter removal, pruning, and pathway upkeep, is required. Too many people will cause other problems, too. More feet on the ground means damage to vegetation, soil compaction, and less biodiversity. It is common in cities with little UGS, where small areas must serve large populations⁴⁹. To address these problems, urban planners can widen green spaces or introduce measures to disperse visitor pressure. For instance, introducing multiple UGS in different neighborhoods can help make pleasant, functional public spaces to complement existing green spaces.

Islamabad’s UGS quantification study can inform policy in several ways. Planning, engaging communities, and providing continuous spatial funding are essential to manage UGS effectively. As per this study, spatial planning should provide UGS for all neighborhoods to ensure an equitable distribution of UGS across all neighborhoods. Rigolon stated that such efforts would help to achieve equitable access to green space for all individuals⁴³. Irrespective of where they live and how much they earn. Involving the community is also vital for sustainable UGS management. Research shows that if green spaces are planned and developed with the input of local communities, it fosters a sense of ownership and responsibility among them, thereby leading to better management and sustainability^50,51,52. Community gardening programs or local “friends of parks” initiatives are examples of public participation that may help manage UGS and encourage residents to engage in environmental safety. It is necessary to provide consistent funding to UGS to resolve maintenance issues and further future green space expansion. Policymakers can consider various methods to fund UGS. For instance, they can create public-private partnerships, raise green bonds, or ask the community for financial help⁴⁷. It is crucial to have Sustainable Funding in rapidly urbanizing cities like Islamabad that rely on a UGS and face competing land use issues that might threaten their future.

Conclusion

In conclusion, this study underscores the pivotal role of UGS in fostering ecological sustainability, social equity, and urban resilience, particularly in rapidly urbanizing cities like Islamabad. By leveraging GIS and high-resolution satellite imagery, the research provides a detailed analysis of the spatial distribution, typologies, and functional value of green spaces across the city. The findings reveal striking disparities, where wealthier neighborhoods enjoy better-maintained parks and green belts, while densely populated and economically underprivileged areas often lack accessible and functional green spaces. This imbalance highlights the urgent need for equitable planning and management of urban greenery.

The research affirms that UGS are more than aesthetic elements; they serve as vital ecological assets by regulating urban microclimates, enhancing biodiversity, managing stormwater, and mitigating the urban heat island effect. Socially, they contribute to community well-being by offering recreation, relaxation, and physical activity spaces. However, the study also identifies significant challenges, such as the uneven distribution, poor maintenance, and underutilization of certain green spaces, which limit their potential to deliver these benefits.

To address these challenges, the study emphasizes the importance of integrating UGS into urban planning policies to ensure equitable access for all city residents, regardless of socioeconomic status. It also highlights the value of community involvement in the upkeep and management of green spaces, fostering a sense of ownership and responsibility among local stakeholders. Sustainable funding mechanisms, such as public-private partnerships, are proposed to ensure UGS’s regular maintenance and future expansion. Moreover, the research advocates for continued use of data-driven decision-making, leveraging GIS tools to monitor and optimize green infrastructure for long-term sustainability. While this study focuses on Zone I, expanding future research to other zones would offer a more comprehensive perspective on UGS distribution and accessibility across the entire city.

This research presents UGS as Nature-Based Solutions (NBS) to tackle pressing urban challenges like climate change, flooding, and social inequalities, offering actionable strategies for policymakers and urban planners. While centered on Islamabad, these findings provide a valuable framework that other rapidly urbanizing cities can adapt to strike a balance between development and ecological integrity. The study reminds that sustainable cities must prioritize green spaces to ensure a livable, equitable, and resilient urban future.