Guwahati: Growing dependence on biomass burning and traditional bioenergy sources has emerged as a major driver of worsening air quality in Northeast India, with a new study revealing that pollution levels in the region have increased by nearly 50 per cent over the past two decades.
The research, published in the journal Atmospheric Environment, found that extensive biomass use for cooking, heating and agricultural activities has pushed much of Northeast India from a “polluted” to a “highly polluted” category, highlighting the need for cleaner bioenergy solutions and stronger rural air-quality measures, EastMojo reported.
The study, conducted by Abhijit Chatterjee and Soumen Raul of the Bose Institute, analysed particulate matter pollution trends across the Indo-Gangetic Plain, Northeast India and the Himalayan region between 2000 and 2024.
Researchers found a sharp rise in carbon-based aerosol pollution across Northeast India, largely linked to biomass burning from slash-and-burn farming practices and the widespread use of firewood, crop residues and other biomass fuels for cooking and heating.
According to the study, levels of organic carbon and sulphate components in particulate matter increased by nearly 50 per cent during 2010–2019 compared with the 2000–2009 period.
The research shows that pollution hotspots, once limited to parts of Assam, Meghalaya and Tripura, have expanded significantly. Much of the Northeast has now crossed into the “highly polluted” category for carbonaceous aerosols.
The study identifies intensified biomass burning as the primary driver of the trend, noting that such practices remain closely tied to rural livelihoods across the region.
Chatterjee said the findings highlight a major gap in India’s clean-air efforts. He noted that while the National Clean Air Programme focuses largely on urban areas, pollution levels in rural regions are also severe and, in some cases, even higher. According to him, emissions from biomass burning used for cooking, heating and agricultural activities are not being adequately addressed.
The study also points to rising industrial pollution in Assam. Researchers found that sulphate emissions in the state increased by more than 30 per cent after the implementation of the National Clean Air Programme. The increase was linked to emissions from thermal power plants, oil refineries and cement factories located in areas including Bongaigaon, Guwahati, Dibrugarh, Digboi, Numaligarh and Bokajan.
While dust pollution showed improvement in districts such as Kokrajhar, Dhubri and Bongaigaon, industrial sulphate emissions continued to increase.
The study also found that Northeast India plays a dual role in regional air pollution. Satellite observations showed the region, along with the eastern Indo-Gangetic Plain, contributes significantly to aerosol pollution over the eastern Himalayas. At the same time, pollution originating from the central and eastern Himalayan regions also affects air quality in the Northeast.
Researchers said the findings underscore the need to broaden India’s clean-air strategy beyond its current focus on 131 non-attainment cities. They recommended incorporating rural areas and environmentally sensitive regions into future air-quality planning.
The study specifically called for the inclusion of Northeast India’s biodiversity-rich ecosystems, along with the Sundarbans and Himalayan regions, in future clean-air frameworks.
According to the researchers, protecting ecologically sensitive landscapes, promoting cleaner bioenergy alternatives and reducing biomass burning will be essential to preventing further deterioration in air quality across Northeast India.
