Farm fires dip may be undercount, ISRO study flags shift in stubble-burning time

The data on farm fire incidents reported by government agencies such as the Indian Agricultural Research Institute (IARI) and various state remote sensing centres is based on information mapped by sun-synchronous polar orbiting satellites such as NOAA’s Suomi National Polar-orbiting Partnership (NPP) and NASA’s Terra MODIS and Aqua MODIS.

The ISRO study used data from the geostationary Meteosat Second Generation (MSG) meteorological satellites equipped with the Spinning Enhanced Visible and Infrared Imager (SEVIRI) that are ownedand operated by the European Organisation for the Exploitation of Meteorological Satellites (EUMETSAT).

The Meteosat-8/9, operating in Indian Ocean Data Coverage (IODC) mode, provides active fire monitoring between latitudes 67.5N and 67.5S and longitudes 22W and 113E, an area that covers all of India.

Geostationary satellites orbit the Earth at a high altitude — about 36,000 km — directly above the equator, and cover a specific region constantly. Polar satellites, by contrast, have low, north-south orbits that pass over the poles, and see a particular area only once or twice every 24 hours.

The MSG-SEVIRI data underline “the importance of geostationary satellites for monitoring diurnal fire dynamics and highlight the implications of altered burning practices for emission inventories, air quality assessments, and mitigation strategies in the region”, says the ISRO study. (‘Evidence of shift in stubble burning timing over northwest India from geostationary satellite observations’, Current Science, November 25, by Nimisha Singh, Rohit Pradhan, Bipasha Paul Shukla, and Mehul R. Pandya.)

“Our analysis shows a gradual shift in peak fire activity from ~13:30 IST in 2020 to ~1700 IST in 2024 to avoid detection by polar orbiting satellites,” the study says. The polar-orbiting satellites — which have been used to estimate crop residue-burning events since 2021 — leave Punjab and Haryana unmonitored approximately between 10.30 am and 1.30 pm, and again from around 2.30 pm to about 10.30 pm.

The shift in peak stubble-burning times became especially conspicuous from 2022 onward, says the study. “Stubble-burning activities in the Punjab and Haryana regions are [now] taking place later (3.30-6 pm) in the day, which means the satellites that have traditionally been used to monitor these fires are now missing them, since their usual passing times are around 11-1330 hrs,” one of the study’s co-authors told The Indian Express.

“Because of this time shift, many burning events are going uncounted, leading to an underestimation of fire activity. Satellites in geostationary orbit have the unique ability to detect such large-scale activities on every-half-hour basis, and a scientific research study has been carried out and results have been published in a scientific journal,” this researcher said.

The use of geostationary satellites to monitor fires on the ground is standard practice in many parts of the world. Earlier this year, this same team of ISRO researchers published a separate study on farm fires using data from the Indian geostationary satellite INSAT-3DS (‘Active Fire Detection using Indian Geostationary Satellite INSAT‑3DS’) in the journal Remote Sensing in Earth Systems Sciences.

According to the researchers, the paper published last month is possibly the first peer-reviewed, data-based study that establishes the shift in crop-burning times.

But the possibility that the polar orbiting satellite data on farm fires, which is used by the government, may not accurately represent the situation on the ground, had been flagged by ISRO to the Commission for Air Quality Management in NCR and Adjoining Areas (CAQM) last year.

CAQM, the primary air pollution watchdog for Delhi-NCR, had apprised the Supreme Court of ISRO’s response in an affidavit submitted on November 21, 2024. Also, three days previously, on November 18, 2024, the top court had been informed that there could be an undercount in the data collected through polar-orbiting US satellites.

The SC was told that data from GEO-KOMPSAT 2A, a geostationary Korean satellite, had picked up fires after NASA’s polar-orbiting satellite had passed. CAQM also told the court that ISRO had informed the Commission that it would develop in-house algorithms to analyse foreign satellite data for more accurate farm-fire counts.

CAQM is learnt to have written to the chief secretaries of Punjab and Haryana this week to say that “paddy stubble burning incidences both detected and undetected by satellites were still [being] reported”, which indicated that effective enforcement of the action plan to eliminate the practice “has not been forthcoming”.

The letter, dated December 1, asked both states to submit their action plans for complete elimination of stubble-burning events.

Top government sources said CAQM had, on November 21, sought a detailed report on “reported fire locations undetected by satellites, methods of stocktaking of such events, and also the effective punitive actions taken by the states for such incidences”.

Officials of the Punjab government told The Indian Express on Wednesday that they were aware of allegations that farm stubble was being set on fire at specific times in order to dodge satellite sweeps. In response, the government had increased monitoring and enforcement efforts that were now ongoing round the clock, the officials said.

“The administration is aware of the alleged shift in the timing of stubble-burning activity on the ground over the last 4-5 years. This point was also raised before the Supreme Court. We took steps and created a system of round-the-clock checking so that there is no gap — when the satellites cannot record the fires, our teams on the ground should do so,” a senior environmental engineer with the Punjab Pollution Control Board (PPCB), who has been involved in monitoring stubble-burning over the past several years, said.

There wasn’t a single day when senior officials did not monitor stubble-burning through daily reports and video conferences during the entire farm-fire season, this official said.

Another official reiterated that “Efforts to target and prevent crop-burning continue round the clock, day and night, during the October-November farm-fire season.” Teams had been designed to operate at all hours — “afternoon, evening, and night” — so that no burning goes unnoticed, the second official said.

Jagdish Singh, joint director, Punjab Agriculture, and nodal officer for the Crop Residue Management (CRM) Scheme, said that CAQM teams that had travelled through fields during evening hours this year had found no more than a couple of fires on the days of checking.

A district magistrate in one of Punjab’s farm-fire hotspot districts said field staff had indeed reported a recent shift in stubble-burning patterns, and that some farmers were choosing to burn crop residues at night in the belief that they could avoid FIRs and the payment of environmental compensation.

To counter this, special teams had been deployed for late-evening patrols, and after a couple of cases of night-time burning were detected, the farmers involved were booked to send the clear message that violations would be penalised regardless of the time of day, the DM, who declined to be named, said.

A farmer from the Majha region conceded that he had been burning stubble in the evening for the past three years to evade action. He had been successful until the last season, but this year, he and a few other farmers had been caught by flying squads late in the evening, the farmer said.

According to the Punjab government, more than 10,500 personnel were deployed this season for round-the-clock monitoring and enforcement to check crop-burning activity. This force was supplemented by flying squads from the Central Pollution Control Board (CPCB) and the CAQM.

In addition, a 1,700-member Parali Protection Force was raised specifically to identify and report fires that might escape detection by satellites.

Under the revised environmental compensation structure notified by CAQM this year, the penalty for stubble-burning is Rs 5,000 per incident for small landholders up to 2 acres, Rs 10,000 for those owning 2-5 acres, and Rs 30,000 for farmers with more than 5 acres of land. Compensation rates until last year were Rs 2,500, Rs 5,000, and Rs 15,000 respectively.

As many as 1,963 FIRs were registered this year under Section 223 (‘Disobedience to order duly promulgated by public servant’) of the Bharatiya Nyaya Sanhita, 2023. Additionally, environmental compensation amounting to Rs 1.26 crore was imposed on violators.

According to official data, the incidence of farm fires in Punjab during the period September 15 to November 30 plummeted from 83,002 in 2020 to just 5,114 this year. 71,304 incidents were recorded in 2021, and 49,922, 36,663, and 10,909 in 2022, 2023, and 2024 respectively.

In Haryana, the incidence of farm fires during the same period fell from 6,987 in 2021 to 1,406 in 2024 and 662 this year.

On December 1, responding to a starred question by Congress Lok Sabha MP Charanjit Singh Channi, Union Environment Minister Bhupender Yadav told Parliament that Punjab and Haryana have “collectively recorded about 90% reduction in fire incidences during paddy harvesting season in the year 2025 in comparison to the same period in the year 2022”.