A comprehensive 25-year satellite study has identified southern Bengal and Bihar as the new epicenters of particulate matter (PM) pollution across the Indo-Gangetic Plain (IGP). The research, published in the journal Atmospheric Environment, warns that elevated carbon pollution has expanded across the entire state of West Bengal, endangering ecologically fragile zones such as the Sundarbans and the Eastern Himalayas.
Study Details and Findings
Led by Professor Abhijit Chatterjee and Soumen Raul of the Bose Institute in Kolkata, the study analyzed air quality data from 2000 to 2024 across the IGP, the Himalayas, and Northeast India. The eastern belt of the IGP—including southern Bengal, Bihar, and large parts of Bangladesh—consistently recorded the worst air quality over the 25-year period, with the crisis worsening rapidly in the last 15 years.
Pollution Trends Over Decades
Between 2010 and 2019, PM pollution in the eastern zone spiked by 10% to 40% compared to the previous decade. From 2020 to 2024, highly toxic "carbonaceous aerosol hotspots," which were largely confined to northern Bengal during the 2000–2009 baseline, expanded to cover the entire state. The study points to biomass burning—including rural biomass used for cooking and heating, as well as urban solid waste burning—as the primary driver, rather than industrial or vehicular emissions.
Impact on the Sundarbans and Eastern Himalayas
The research highlights a critical threat to the Sundarbans, the world's largest mangrove ecosystem, which is already suffering from rising sea levels, coastal flooding, and erosion. The study advocates for the immediate inclusion of the Sundarbans in India's clean air mission, noting that current policies focus almost exclusively on major cities, leaving vulnerable rural communities and ecosystems unprotected.
Atmospheric trajectory modeling shows that wind patterns carry heavy aerosol loads from the lower IGP—including Bihar, Bengal, and Bangladesh—into the ecologically sensitive Eastern Himalayas. These mountain zones lack structured clean air interventions or monitoring infrastructure, yet they bear the brunt of emissions from hundreds of miles away.
Policy Recommendations
Despite improvements in urban PM levels since the launch of the National Clean Air Programme (NCAP), pollution from biomass burning has remained stubbornly flat in Bengal. The researchers argue that the Central Pollution Control Board (CPCB) must fundamentally restructure its clean air strategy. While the CPCB acknowledges gaps in rural monitoring, this 25-year dataset provides the hard evidence needed to force a policy shift.
"The eastern Indo-Gangetic Plain, and increasingly Northeast India, are carrying a disproportionate pollution burden driven almost entirely by biomass burning. That is the signal that stands out most clearly across 25 years of data," said Professor Chatterjee.
