Table 4 Data sources and processing methods for EI.

Water body area ratio

Water body area/land cover area; water body area derived from the CLCD land cover dataset⁴¹; land cover area includes nine main types of land cover such as cultivated land, forest land, grassland, water, urban land, wetland, sandy land, bare land and ice and snow, derived from the CLCD land cover dataset. all processed through ArcGIS

Wetland area ratio

Wetland area/land cover area; wetland area derived from the CLCD land cover dataset⁴¹; processed through ArcGIS

Per capita urban green area

Urban green area/person; urban green area sourced from the National Bureau of Statistics

Forest coverage rate

National Bureau of Statistics

Green coverage rate in built-up areas

National Bureau of Statistics

Per capita park number

Capita park number/person; capita park number data sourced from the China Statistical Yearbook

Per capita park area

Capita park area/person; capita park area data sourced from the China Statistical Yearbook

Road area ratio

Road area/land cover area; road area sourced from the National Bureau of Statistics and the China Statistical Yearbook

Nighttime light data value

Obtained from calibrated annual data of DMSP-OLS-like nighttime light from 1992–2022 for China; integrated from DMSP-OLS and SNPP-VIIRS data⁴²

Built-up area ratio

Built-up area/land cover area; built-up area sourced from the National Bureau of Statistics and the China Statistical Yearbook

Investment in industrial pollution control as a percentage of GDP

Investment in industrial pollution control/GDP; investment in industrial pollution control sourced from the China Environmental Statistics Yearbook

Investment in urban environmental infrastructure construction as a percentage of GDP

Investment in EI construction/GDP; investment in EI construction sourced from the China Environmental Statistics Yearbook

Urban sewage treatment rate

China Environmental Statistics Yearbook

Urban domestic waste harmless treatment

China Environmental Statistics Yearbook

Comprehensive utilization rate of industrial solid waste

China Environmental Statistics Yearbook

Annual average PM₁₀ concentration

Provincial environmental statistics bulletins

Annual average SO₂ concentration

Provincial environmental statistics bulletins

Annual average NO₂ concentration

Provincial environmental statistics bulletins

Chemical oxygen demand emission intensity

Chemical oxygen demand emission/GDP; chemical oxygen demand emission sourced from the China Environmental Statistics Yearbook

Ammonia nitrogen emission intensity

Ammonia nitrogen emission/GDP, sourced from the China Environmental Statistics Yearbook

SO₂ emission intensity

SO₂ emission/GDP, sourced from the China Environmental Statistics Yearbook