Industrial activity, coal burning and traffic emissions contribute to toxic air pollution in eastern India, where elevated levels of carcinogenic combustion chemicals in PM2.5 were found. Credit: Shankar, S. CC BY 2.0 via Wikimedia Commons
Air pollution across India’s industrial belts carries a hidden toxic load: polycyclic aromatic hydrocarbons (PAHs), a class of chemicals linked to cancer and other health risks. A new study provides a detailed picture of how these pollutants accumulate in fine particulate matter (PM2.5) in eastern India1.
Researchers at the Indian Institute of Technology Delhi conducted year-long monitoring across four sites in the industrial corridor of West Bengal, including Durgapur and Raniganj. Sampling industrial, residential and commercial locations every three days through 2023, they analysed 484 PM2.5 samples to identify and quantify PAHs using thermal desorption gas chromatography–mass spectrometry.
Industrial zones showed the highest pollution levels. Average total PAH concentrations reached about 494 nanogram per cubic metre (ng/m3) at Raniganj and 416 ng/m3 at an industrial site in Durgapur, substantially higher than residential and commercial areas. Among the detected compounds, indeno[1,2,3-cd]pyrene, benzo[ghi]perylene and benzo(b+k)fluoranthene dominated the mixture, with four-ring PAHs contributing the largest share.
Source analysis using diagnostic ratios and principal component analysis pointed to a mix of combustion sources — including coal use, biomass burning, diesel and gasoline vehicles, and wood combustion. Health-risk calculations suggested cause for concern: estimated inhalation cancer risks for both adults and children exceeded recommended safety thresholds across all sites.
The findings highlight how industrial activity, transport emissions and household fuel use combine to drive toxic air pollution in the eastern Indo-Gangetic Plain. Targeted emission controls and cleaner energy transitions, the authors say, are essential to reduce exposure and protect public health.
