Why Burning Crop Residue Releases Four Distinct Pollutants

1.1 Why do farmers choose fire?

They choose fire because the gap between harvest and sowing is very short. Studies put it at around two to three weeks. Farmers say they have only 10 to 15 days. Fire clears the field fast and costs little.

1.2 How much straw is there?

There is a huge amount. A CSE brief estimated that Punjab alone produced 17 to 18 million tonnes of paddy straw. For 2026, states estimate 2.762 crore tonnes (27.62 million tonnes) of stubble in the paddy harvest.

The figures come from different years and sources, so do not add them together.

1.3 What else does burning destroy?

It destroys plant nutrients that the soil needs. Burning crop residue in one year alone loses 1.43 million tonnes of nutrients from the topsoil layer, says CSE.

2.1 Why does burning release carbon monoxide?

Carbon monoxide (CO) is released whenever something is burned, says the US EPA. A smouldering fire gives off more of it than a flaming one. A study found smouldering gave more CO, particles and unburned hydrocarbons than flaming.

2.2 Why is a smouldering fire dirtier?

It is dirtier because it burns slowly and less completely. Flaming combustion is hotter and more efficient. Smouldering is the slow type, with a low combustion efficiency. Wet straw tends to smoulder.

2.3 Why does methane come out?

Methane is a hydrocarbon, and smouldering leaves hydrocarbons unburned. A cited study reports that wetter residue raises emissions of carbon monoxide, methane and organic carbon. Methane is a greenhouse gas, so it adds to warming as well as smoke.

2.4 Why does sulphur dioxide appear?

Straw contains sulphur, and fire frees it. CSE notes that about half the sulphur in crop residue is lost through emissions when it burns. A farm fire is still a small source of SO2. Most comes from burning fossil fuels in power plants and industry.

2.5 Why is ozone different?

Ozone is not emitted by the fire at all. Ground-level ozone forms when oxides of nitrogen (NOx) and volatile organic compounds (VOCs) react in sunlight. Fire smoke carries both ingredients, so ozone appears later and downwind.

NASA notes that this smoke also holds nitrogen oxides and particulate matter.

3.1 How far have fire counts fallen?

Satellite counts in Punjab have dropped sharply. Between 15 September and 21 October, Punjab recorded 415 fires in 2025, the lowest in six years. The same window had 10,791 in 2020. That is about a 96% decline.

3.2 Is it falling everywhere?

No. Uttar Pradesh recorded 660 fires in the same window of 2025. That is the second-highest figure since 2020. Haryana, like Punjab, fell sharply.

3.3 Why can a count mislead?

A count can mislead because satellites see only part of the day. The government system looks from 10.30 am to 1.30 pm. Farmers have shifted burning to later hours.

An iFOREST report found that over 90% of large Punjab fires in 2024 and 2025 came after 3 pm. In 2021 only 3% did.

3.4 What does burnt area show?

Burnt-area mapping shows a real but smaller fall. Punjab’s burnt area fell 37%. The area was 31,447 sq km in 2022 and about 20,000 sq km in 2025. Together, Punjab and Haryana cut burnt area by 25 to 35%, says iFOREST. About 30,000 sq km still burned in 2025.

4.1 What is the Pusa Decomposer?

It is a microbial solution made by IARI, Pusa, to rot stubble in the field. It contains seven fungal species. Four capsules are enough for one hectare. Farmers spray it so they need not burn.

4.2 How widely was it used?

Early reach was modest. In 2020-21 it went to farmers in 25 states, covering over 10,000 hectares. Delhi’s Chief Minister urged the Centre in 2021 to ask neighbouring states to use it.

4.3 What does the Happy Seeder do?

It sows the next crop without clearing the field. It places seed and fertiliser in one pass, with no tilling and little soil disturbance. Farmers can sow wheat straight through the paddy residue.

4.4 What is ex-situ use?

Ex-situ means the straw is taken off the field and used elsewhere. The ministries want more use in biomass power plants, compressed biogas units, ethanol plants and pellet units. In Punjab, straw put to use rose from 5.96 to 7.06 million tonnes in 2025.

5.1 What is the CRM scheme?

It is the Centre’s Crop Residue Management scheme, started in 2018-19 to deal with stubble burning. It has paid for over 3.54 lakh machines and more than 43,500 Custom Hiring Centres. For 2026-27 the provision is Rs 544.15 crore, and Rs 272.07 crore was released as the first instalment.

Source: The Tribune, from a CAQM reply to an RTI request.

5.2 What did CAQM plan for 2025?

CAQM issued a 19-point plan to end paddy stubble burning. Nodal officers watch groups of no more than 50 farmers. CAQM also proposed district and block-level “Parali Protection Forces”. See CAQM: From Advice to Enforcement for the body itself.

5.3 What happened in the Supreme Court?

On 24 September 2024 the Supreme Court said it wanted an answer from CAQM on stubble burning. Section 14 of the CAQM Act sets penalties for breaking its orders. That hearing was in 2024, not 2026.

5.4 What changed for winter 2026?

CAQM approved a revised Graded Response Action Plan (GRAP) schedule, reported on 29 September 2026. It has 25 actions under Stage I, eight under Stage II, ten under Stage III and five under Stage IV. BS-III petrol and BS-IV diesel vehicle curbs now reach Sonipat.

5.5 Have enforcement numbers moved?

Yes. FIRs against farmers fell 66%. Even so, November 2025 was among the second most polluted in five years, an RTI applicant noted. Stubble is one source among many.

6.1 What does burning cost in money?

An IFPRI-led study estimated the economic loss at over USD 30 billion a year. It was the first study to estimate health and economic costs of crop residue burning in northern India (2019).

6.2 Who is hurt most?

Children under five are hurt most. Living in districts with intense burning is a leading risk factor for acute respiratory infection (ARI) in that age group.

6.3 How many deaths are linked?

A later study estimated 44,000 to 98,000 premature deaths a year from 2003 to 2019. Punjab, Haryana and Uttar Pradesh gave 67 to 90% of them. Burning two hours earlier in Punjab alone could avert up to 9,600 deaths a year.

7.1 What did UPSC ask?

7.2 Why are all four correct?

All four are correct because three come from the burning and one forms from its smoke. CO, methane and SO2 come out directly. Ozone forms later from NOx and VOCs in sunlight. The question says released into the atmosphere, so all four count.

7.3 Which mix-ups come up?

• Ozone is not emitted. It forms afterwards.
• Smoke is not only particles. Gases are released too.
• Falling fire counts. They do not prove that less burning happens.
• SO2 source. Fossil fuels are the largest source, not farm fires.