The discrepancy between satellite tv for pc knowledge of farm fires and air air pollution | Defined

The story to date: The air high quality within the nationwide capital has been struggling to get better from the lows to which it dropped proper after Deepavali regardless of the implementation of GRAP stage IV measures, the lively intervention of the Supreme Court docket, and stop-gap measures by the Delhi authorities. Many fingers are presently pointed on the farm fires within the surrounding states, the place farmers are burning paddy stubble in time for the wheat-sowing season. Whereas these fires aren’t solely liable for Delhi’s plight, an issue over measuring their prevalence illustrates the quantity of consideration they’re receiving.

How are the fires counted?

Farmers in Punjab and Haryana sow rice within the kharif season and harvest it in November, utilizing the summer time monsoons to quench the crop’s excessive water demand. After the rice is harvested, they should clear the leftover natural materials — known as paddy stubble — with a view to make means for the following sowing season. For causes of time and value, they’ve historically most popular to burn the stubble.

However due to the winds presently of the yr over the Nationwide Capital Area, the poisonous particulate matter from the fires is floated to and hangs over New Delhi, dragging its air high quality down.

Due to the big space over which farmers mild the fires, officers have stated satellites are the easiest way to trace the fires. The Indian authorities presently procures this knowledge from two NASA satellites known as Aqua and Suomi-NPP.

NASA launched Aqua in 2002 and it’s presently within the twilight stage of its designed lifespan. Its Reasonable Decision Imaging Spectroradiometer (MODIS) instrument was constructed to trace adjustments within the decrease environment, particularly over land, by way of time. MODIS’s technical successor is the Seen Infrared Imaging Radiometer Suite (VIIRS) instrument onboard Suomi-NPP, which NASA launched in 2011. Each satellites are a part of NASA’s ‘Earth Observing System’.

Aqua’s and Suomi-NPP’s overpass at every location occurs at 1.30 pm native time within the day and at 1.30 am native time at evening. Their MODIS and VIIRS devices gather high-resolution seen and infrared pictures of the earth at round these intervals and are able to recognizing fires and smoke in a small window centred on the overpass time.

What’s the new controversy?

On October 2, a senior scientist at NASA’s Goddard House Flight Centre named Hiren Jethva wrote on X (Twitter) that there have been 40% fewer farm fires than predicted in 2023 and expressed hope for the development to proceed this yr. On October 24, Jethva wrote in the identical thread that the variety of fires in 2024 gave the impression to be the “lowest in [the] final decade”, and added that both “floor efforts to curb residue-burning seem like working or burning actions [are] happening after satellite tv for pc overpass time, however it wants ground-truthing”.

His put up implied farmers have been burning paddy stubble after the Aqua and Suomi-NPP satellites had accomplished their overpass at round 1.30 pm.

The subsequent day Jethva adopted up by evaluating knowledge from Aqua and Suomi-NPP with knowledge from the GEO-KOMPSAT 2A satellite tv for pc. South Korea launched this satellite tv for pc, additionally known as Cheollian 2A, in 2018 as a “devoted geostationary climate satellite tv for pc”; it’s presently stationed at 128.2º E and has a deliberate mission lifetime of no less than a decade.

Within the visuals Jethva collected and offered from the three satellites, the smoke cowl over cropland in Punjab and Haryana appeared to thicken after Aqua and Suomi-NPP had accomplished their overpass, as if farmers have been lighting extra fires later within the day from earlier than.

The senior scientist additionally wrote that the amount of aerosols within the air was roughly the identical as in earlier years whereas it ought to’ve been decrease given Aqua and Suomi-NPP indicated there have been fewer fires.

Is the discrepancy actual?

In 2020, the Indian authorities created the Fee for Air High quality Administration within the NCR and Adjoining Areas (CAQM for brief) by ordinance and a subsequent Act of Parliament in 2021. Its mandate was to check, determine, and resolve points related to bettering air high quality in its jurisdiction.

On November 23, The Hindu reported primarily based on a number of sources and paperwork that the CAQM was conscious farmers have been burning paddy stubble after the NASA satellites had accomplished their overpass to keep away from being detected. Nevertheless the CAQM has continued to insist within the public that the variety of farm fires has dropped, defending its conclusion within the face of opposite proof by claiming it used totally different formulae.

That farmers have been conscious of the overpass timings is recorded within the minutes of a March 7, 2024, assembly, the place director of Haryana House Purposes Centre Sultan Singh and Nationwide Distant Sensing Centre (NRSC) scientist Bhavana Sahay alleged as a lot. Farmers on the bottom additionally advised The Hindu a authorities official had requested them to mild fires after 4 pm.

(The alleged recommendation echoes Goodhart’s regulation: “when a measure turns into a goal, it ceases to be a great measure”.)

The CAQM has additionally come beneath the pump from a second angle: in affidavits to the Supreme Court docket, it has stated the burnt space in Punjab shrunk 26.5% between 2022 and 2023 whereas knowledge from the Authorities of Punjab and the Indian Agricultural Analysis Institute, which is funded by the Centre, says it elevated 24% and 15% respectively.

How is the federal government responding?

The Centre had initially created the CAQM to switch the Environmental Air pollution (Prevention and Management) Authority (EPCA), which the Supreme Court docket had created in 1998. EPCA was a non-statutory physique and lacked the devices to sanction non-compliant actors. CAQM was designed to have enamel within the 2021 Act — and which it has since been accused of not wielding.

The Supreme Court docket particularly has upbraided the CAQM for failing to mitigate air air pollution ensuing from the fires through the years. The physique is anticipated to reply on November 25 to the Supreme Court docket to allegations that it was conscious farmers have been delaying burns to after the satellites’ overpass.The Indian authorities can also be on the again foot after Union agriculture minister Shivraj Singh Chouhan stated on October 26 that the variety of stubble-burning incidents have dropped this yr.

However the CAQM has additionally maintained that its efforts have lowered the prevalence of fires by 71% in Punjab and 44% in Haryana between 2020 and 2024, and has objected to the thought of a bunch of retired judges overseeing the struggle towards stubble-burning.

The CAQM additionally stated it wrote to the NRSC — a physique beneath the Indian House Analysis Organisation (ISRO) — asking it to develop a regular protocol to measure burnt space in January 2024. At current, burnt space knowledge is obtainable as soon as each 5 days from the Sentinel II satellites of the European House Company.

Can Indian satellites assist?

In an affidavit to the Supreme Court docket on November 21, the CAQM stated ISRO plans to judge the usability of knowledge from numerous satellites to determine farm fires. In line with the affidavit, ISRO specialists are of the view that knowledge from INSAT-3DR (by India), GEO-KOMPSAT 2-AMI (South Korea), Meteosat-9, Feng Yun-4A/4B (China), and HIMAWARI-8 (Japan) can’t present account fireplace counts — though their assessments received’t be full for no less than one other month.

The issue with INSAT-3DR is that its knowledge is simply too coarse: of 1 km in seen and short-wave infrared radiation, of 4 km in center and thermal infrared, and of 8 km for water vapour.

ISRO additionally operates the three RESOURCESAT satellites, launched in 2003, 2011, and 2016, with related payloads. These in RESOURCESAT 2A have higher options, nonetheless. The Linear Imaging Self Scanner (LISS) cameras 3 and 4, each of which ‘see’ in seen and near-infrared radiation; LISS-4 has a spatial decision of 5.8 m and LISS-3, of 23.5 m. The Superior Extensive Discipline Sensor (AWiFS) digicam detects related radiation at a fair decrease decision of 56 m.