North Indian rice farmers appear to be finding ways to outsmart the satellite monitoring systems designed to detect and deter the burning of crop residue, a major contributor to the region's air pollution. A recent study by the Indian Space Research Organisation (ISRO) suggests that farmers in Punjab and Haryana have shifted the timing of stubble burning to the evening hours, specifically to avoid detection by polar-orbiting satellites. This strategic adjustment potentially leads to an underestimation of farm fire counts and challenges claims of a significant decline in such incidents.
The study, published in Current Science on November 24, 2025, analyzed data from 2020 to 2024 and revealed a distinct change in the timing of fire activity. While stubble fires previously peaked between 12 pm and 2 pm, they now tend to occur around 5 pm to 6 pm, after NASA satellites have passed over the region. This shift indicates a calculated effort by farmers to circumvent satellite surveillance.
Hiren Jethwa, an aerosol remote sensing scientist at NASA Goddard Space Flight Center, noted that a South Korean geostationary satellite confirms that the majority of crop burning happens after 2 pm, when NASA satellites are no longer monitoring the area. These geostationary satellites, which take images of the region every five minutes, are able to capture the fires that might be missed by others.
The findings of the ISRO study contradict the Commission for Air Quality Management's (CAQM) statement from earlier in the week, which claimed a nearly 90 percent drop in farm fires in Punjab and Haryana between 2020 and 2024. While the CAQM standardized its fire detection methodology in August 2021 using data from NASA's MODIS and VIIRS satellites, the change in burning patterns raises questions about the accuracy of these figures.
Some experts, however, dispute the claim that farmers are intentionally evading satellite detection. Ravindra Khaiwal, an expert on public and environmental health from the Post Graduate Institute of Medical Education and Research (PGIMER) in Chandigarh, stated that over 95% of fires are detected in the morning. He attributes the reduction in fire counts to improved enforcement and alternative practices. Similarly, the Punjab Pollution Control Board chairman, Adarshpal Vig, stated that their data also captures fire incidents at night and that the idea of farmers avoiding detection is merely a "figment of imagination".
Despite differing opinions, the shift in burning times, along with satellite imagery showing widespread smog, has raised concerns about the true extent of stubble burning and its impact on air quality. Delhi's Air Quality Index (AQI) reached a concerning 428 on November 15, 2024, its worst reading of the season, highlighting the severity of the pollution.
With approximately 28,000 square kilometers of crop area burned in Punjab and Haryana in 2025, the contribution of these fires to North India's air pollution is likely higher than current estimates suggest. As the debate continues, it is clear that a more comprehensive and nuanced approach is needed to accurately assess and address the issue of stubble burning and its impact on the region's air quality. This includes considering data from multiple satellite sources, on-the-ground verification, and an understanding of farmers' practices and challenges.
