Satellite study finds PM pollution rose over 20% across the Indo-Gangetic Plain

Mumbai: A satellite-based study analysing 25 years of data across the Indo-Gangetic Plain (IGP), the Himalayan region, and North-East India has found that overall particulate matter (PM) pollution increased by more than 20 per cent during 2010–2019 compared to the 2000–2009 baseline.

The study used satellite-based remote sensing data, validated with ground-based observations, to achieve the spatial coverage and temporal continuity required for a long-term assessment spanning 2000 to 2024.

The research was led by Prof Abhijit Chatterjee of the Bose Institute, Kolkata, with Soumen Raul serving as the principal research fellow.

According to the findings, particulate matter pollution across the Indo-Gangetic Plain rose by more than 20 per cent within a decade, with Bihar and West Bengal remaining the worst-affected regions. Researchers said the situation continues to deteriorate.

In North-East India, pollution linked to biomass burning increased by nearly 50 per cent, pushing much of the region from the “polluted” to the “highly polluted” category over the past two decades.

The study identified biomass burning for cooking, heating and agricultural activities as the primary contributor to pollution, rather than industries or vehicular emissions. Urban waste burning was also found to be adding to the pollution burden.

Researchers warned that the pollution is no longer confined to its source regions. Trajectory analysis showed that emissions from the Indo-Gangetic Plain are reaching the Himalayas, with pollutants from Punjab and Delhi affecting the western Himalayan ranges, while emissions from Bihar and West Bengal are influencing the eastern Himalayas — regions that currently lack dedicated clean air programmes.

The study noted that while India’s National Clean Air Programme (NCAP) has delivered some improvements in urban areas, it has not adequately addressed biomass burning or pollution in rural regions. The researchers called for an expanded “NCAP 2.0” that would include rural areas, the Sundarbans, North-East India and the Himalayan belt.

“NCAP is primarily designed as a city-focused initiative. But our data shows that air pollution in rural India is equally severe, and in some cases even more so. Biomass burning — for cooking, heating and agriculture — is not being adequately addressed by the programme in its current form. The rural dimension needs to be explicitly integrated into the clean air mission,” said Prof Chatterjee.

“The Himalayas are not insulated from IGP pollution. Our trajectory analysis shows that what is emitted in Punjab or Bihar does not remain there — it travels into the mountains. These are ecologically and climatically sensitive zones, and they are currently outside the scope of any structured clean air intervention in India,” Raul added.