The Environment Ministry has repeatedly claimed that the number of fires in Punjab and Haryana has fallen by 92% and 90% from 2021, respectively, citing a sharp decline in stubble burning and the effectiveness of measures in both states. File | Photo credit: The Hindu
Using “fire counts”—satellite-derived estimates of active fires—to measure the extent of stubble burning in Punjab and Haryana can be misleading.
The Environment Ministry has repeatedly claimed that the number of fires in Punjab and Haryana has fallen by 92% and 90% from 2021, respectively, citing a sharp decline in stubble burning and the effectiveness of measures in both states.
However, when data from another satellite was used to calculate another parameter called “burnt area” – the actual area of land affected by fire – the reduction was more gradual, by around 30%, falling from around 31,500 km² in 2022 to 19,700 km² in 2025 (as of November 25), according to a study that analyzed data from the iForest satellite. burning in Punjab and Haryana.
“The government should stop using fire numbers as a proxy to measure the decline or increase in stubble burning,” iForest CEO Chandra Bhushan said, adding: “Smoke detected by satellite sensors offers a better view of burned land. Satellites often miss small fires.”
Currently, all Indian official estimates rely on data provided by the Consortium for Research on Agroecosystem Monitoring and Modeling from Space (CREAMS) of the Indian Agricultural Research Institute (IARI) and are based on NASA’s Moderate Resolution Imaging Spectroradiometer (MODIS) on the Terra and Aqua satellites and the Visible Infrared Imaging Satellite on the Sui Sui Radiometer Suite (VINIRS).
These satellites orbit the Earth’s poles and observe India only at a fixed time of day, from 10:30 AM to 1:30 PM. Their sensors are only able to pick up active fires and are unable to calculate the actual number of fires in, say, 24 hours.
“These monitoring gaps have far-reaching implications. Fires missed by polar satellite sensors lead to underestimation of emissions, mischaracterized aerosol and particulate loads, and incorrect simulations of air quality dynamics across India,” noted an iForest press release. “For example, the contribution of stubble burning to air pollution in Delhi was greatly underestimated this year because MODIS/VIIRS captured only a small fraction of the number of active fires. This bias is now affecting policy-making and regulatory action, and weakening the evidence on which interventions are designed.”
To arrive at estimates of burned area, iForest used data from the Sentinel multispectral instrument. Although it is also a polar-orbiting satellite, it flies over India only about once every five days and its data is only available with a delay of 8-15 days, it is the only one of its kind capable of calculating “burnt area” at a resolution of 100m by 100m.
Another set of satellite data used in the analysis was Meteosat 8 and 9 with the Spinning Enhanced Visible and Infrared Imager (SEVIRI) sensors. Unlike other satellites, this one is “geostationary”, meaning it is always looking at the same location and can therefore provide data every 15 minutes. However, this satellite cannot calculate “burnt area” and can only calculate fire counts (like MODIS and VIIRS). Located 36,000 km from Earth, it was only able to detect “large fires” at a much coarser resolution of 4 km by 6 km. “Although it may not provide accurate information on the number of fires, this satellite data clearly showed that since 2022, most of the fires were concentrated in the evening hours – outside the detection time of the polar satellites. In Haryana, fires were always started around the evening. Which means that the actual number of fires in the state was always underestimated,” said Mr. Bhushan.
A study published last month in the peer-reviewed journal Current Science, led by scientists at the Space Applications Centre, ISRO, also used SEVERI data to highlight that stubble burning had shifted towards the evening to avoid polar satellites and that there was an increasing fire trend over Punjab from 2020 to 2024, while VIIRS and MODIS data indicated a decreasing trend. In their study, the researchers said that for an accurate picture of stubble burning, data from both polar and geostationary satellites should be used.
Although the government is aware of the limitations of its satellite analysis and has been ordered by the Supreme Court to conduct a “more thorough” investigation into the number of fires “in the evening”, it has yet to publicly release data on burned areas, citing methodological limitations. “While there has been some success in reducing farm fires in Punjab, much more work is needed. The contribution of stubble burning is much greater than the 5 to 10 percent currently estimated,” Bhushan added.
Published – 8 Dec 2025 23:05 IST
