Mint Explainer | Dirty air trick: How North Indian rice farmers outsmart satellites

Mint explains how the study arrived at the conclusion and its implications.

What did the study find?

Burning of paddy stubble during the months of October and November is a significant contributor to poor air quality in North India.

In 2025, official figures from the Indian Agricultural Research Institute (IARI), which uses active fire-count data from MODIS (Moderate Resolution Imaging Spectroradiometer) and VIIRS (Visible Infrared Imaging Radiometer Suite) sensors aboard polar-orbiting satellites, showed that active fire counts fell by over 90% in Punjab and Haryana since their peak in 2021.

However, the iForest study showed that the majority of farm fires were lit after 3pm—well after the satellites’ pass over between 10:30am and 1:30pm.

How did the study come to this conclusion?

The iForest study used data from geostationary satellites to determine the burnt area. The analysis showed that nearly 20,000 sq. km of crop area was burnt in Punjab and another 8,800 sq. km in Haryana in 2025.

The analysis showed a reduction in farm fires in the range of 25-35% since 2020, but not the sharp decline of 95% as suggested by the active fire-count analysis.

The study advised that the Decision Support System (DSS) for air-quality management in New Delhi, run by the Indian Institute of Tropical Meteorology, should revise its methodology to accurately quantify the contribution of stubble burning to the air-pollution loads in the National Capital Region.

What are the findings' implications?

Farm fires are now estimated to contribute between 5-10% to the winter air pollution load. Although the problem is episodic and limited to October and November, the iForest study warns that stubble burning cannot be overlooked.

Additionally, even the active-fire-count data shows that crop burning has spread to Uttar Pradesh, Rajasthan and Madhya Pradesh due to more farmers planting Kharif paddy (rice). Without a proper idea of the contribution of stubble burning, policymakers may be barking up the wrong tree.

Why are farmers planting more rice?

The area under Kharif rice production increased by nearly 9% between 2022-23 and 2025-26. Farmers are planting more rice because of the lower risks associated with the crop. Rice grows more, is more sturdy, and enjoys a price support due to assured government purchases.

No other crop can compete with the per-acre earnings that rice offers. Farmers often end up burning the stubble left after mechanical harvesting of the crop because they must plant the next wheat crop quickly, as a delay can result in yield loss.

One way to reduce stubble burning is to persuade farmers to grow more oilseeds and pulses, where India is dependent on imports, according to experts.

Is stubble burning the only culprit?

Of course not. A host of other factors are at play. These include vehicular pollution, coal-based power plants, industries and brick kilns, as well as the use of solid fuels (like firewood) for cooking and winter heating. Of particular concern is the open burning of solid fuels, such as paddy stubble.

According to iForest, the pollution generated from a kilogramme of stubble is equivalent to burning a tonne of automobile fuel. The intensity of this pollution is very high because there is no filtering mechanism in place.

A 2023 study published in the journal Environmental Science & Technology found that India could avoid over 700,000 deaths every year by eliminating residential combustion or the use of solid fuels for cooking and heating.