വൈക്കോൽ കത്തിക്കൽ: വടക്കേ ഇന്ത്യയിലെ വായുമലിനീകരണത്തിന് പിന്നിലെ യഥാർത്ഥ കാരണങ്ങൾ എന്തൊക്കെയാണ്?

Stubble burning is the result of a combination of legal, technological and economic factors, including the paddy-wheat cycle, assured procurement and a narrow window between crops; a lasting solution needs stronger incentives for diversification, better residue management and more reliable measurement of burning

It is that time of the year when air pollution in North India, and in Delhi in particular, takes centre stage in public discourse. One oft-cited reason for the worsening air quality index (AQI) is stubble burning by farmers.

Why farmers burn stubble

Stubble burning is the practice of setting fire to crop residue, consisting of the lower parts of plants left after harvesting. This practice is prevalent from the beginning of October to the end of November across northwest India, especially in Punjab, Haryana, and parts of Uttar Pradesh. Stubble burning is mainly associated with the burning of paddy straw in Punjab and Haryana, which together produce around 29 million metric tons of paddy straw. Stubble burning releases large amounts of particulate matter, carbon monoxide, volatile organic compounds (VOCs), and other carcinogenic substances, which together form a thick smog that can harm human health. It also leads to a loss of soil fertility by depleting nitrogen, sulphur, potash, phosphorus, and other micronutrients. The heat generated by stubble burning results in a loss of soil moisture and organic content, which, in turn, leads to increased use of fertilizers in the next crop cycle.

Stubble burning is not a new phenomenon. It has been practised in Punjab since the late 1970s and early 1980s, largely following the introduction of combine harvesters, which leave a portion of the plant in the soil after harvesting. What has changed is its timing, which now coincides with the winter months in North India. This shift in timing followed the enactment of the Punjab Preservation of Sub-Soil Water Act, 2009 (PPSSWA 2009).

In 2012, nearly 73% of the cropped area in Punjab was irrigated using groundwater resources. There was a deficit of 14.31 billion cubic metres, which was met through excessive withdrawal of groundwater. Groundwater levels in Punjab declined at an alarming rate of 0.36 metres annually between 1999 and 2009, driven by intense over-exploitation for agriculture. A landmark NASA GRACE satellite study in 2009 showed that the region comprising Punjab, Haryana and Rajasthan lost 109 cubic kilometres of groundwater between 2002 and 2008 alone, which was considered the largest instance of groundwater depletion in the world at the time.

Water crisis

The PPSSWA 2009 was a result of this alarming situation. The main goal of the Act was to prevent rapid groundwater depletion by prohibiting early paddy nursery sowing and transplantation before the arrival of the monsoon rains. The Act prohibited farmers from sowing paddy before May 10 and transplanting it before June 10, thus delaying paddy transplantation to align with the monsoon season. To ensure compliance, the Act prescribed stringent punishments. Implementing officers were authorised to destroy paddy sown in contravention of the Act and impose a penalty of ₹10,000 per hectare for every month of contravention. These actions by officials were also exempt from legal scrutiny

These sowing restrictions under PPSSWA 2009 pushed the paddy harvest to late October and early November, leaving farmers a narrow 10-15-day window to prepare their fields for the next wheat crop and reducing the time available for sowing. The PUSA-44 variety, which produces higher yields but takes 150-160 days to harvest, further narrowed the window between paddy harvesting and wheat sowing. Combine harvesters, which leave about a foot of stubble behind, put heavy pressure on farmers to clear the crop residue in a very short time. Manual clearing is time-consuming and expensive. Together, these factors made stubble burning almost a necessity for farmers.

The moot point is why farmers continue to grow paddy and wheat despite a stringent legal framework and depleting groundwater levels. The answer lies in the incentive structure built for these two crops. The present minimum support price and procurement framework heavily favours rice and wheat procurement in Punjab and Haryana. Between 2012 and 2024, average paddy procurement in India was about 37% of production. The corresponding figures for Punjab and Haryana were 87% and 74%, respectively, more than double the national average. The pattern is similar for wheat, with procurement accounting for 30% of production nationally, compared with 70% in Punjab and 63% in Haryana. It needs to be noted that the computation of national averages includes Punjab and Haryana, and if these two States are excluded, the differences could be even higher. Such a system provides assured incomes to producers of these two crops in these two States, discouraging them from diversifying into other crops. In addition, power is free for farmers in Punjab and almost free in Haryana. This further encourages farmers to grow water-intensive crops like paddy and wheat through groundwater extraction.

Incentive problem

The technical solutions to stubble burning fall broadly into two categories: in-situ measures that include the use of crop residue management (CRM) machines such as Happy Seeders, Super Seeders and Rotavators; short-duration rice varieties; and direct seeding of rice; and ex-situ measures that involve using crop residue for alternative energy production, such as bio-ethanol and compressed biogas. However, both approaches face formidable problems. Happy Seeders and Super Seeders require an expensive 60-horsepower (HP) tractor, which remains unused for most of the year. Even hiring one typically costs a farmer ₹10,000 and involves a long waiting period. Ex-situ measures cost ₹1,500-₹2,500 per acre, a significant expense for many farmers.

The economic approach to address stubble burning involves building an incentive structure for farmers to diversify from paddy to other crops. The National Green Tribunal ruled in 2018 that farmers who burn stubble could be excluded from the purview of the minimum support price (MSP) policy. The Supreme Court upheld this view in 2023. During the stubble burning season of 2025, 31 flying squads by CPCB were deployed in 18 districts of Punjab and 13 districts of Haryana, involving 10,500 field functionaries in Punjab and 10,000 in Haryana.

Commission for Air Quality Management (CAQM) has directed that complaints be filed before the judiciary against the officials responsible for the lack of effective monitoring. The Parliamentary Committee on air quality, however, advocated that penalising farmers should be the last resort. The Committee recommended setting a minimum price covering all the costs for selling stubble for ex-situ measures, which can ensure farmers' guaranteed income.

The government of Punjab mostly adopted in-situ CRM-based measures and limited ex-situ initiatives. CAQM observed in 2025 that a lot is required to be done in Punjab in terms of timely availability of CRM machinery, necessary support for CBG plants and other industries utilizing paddy straw, and better enforcement. On the other hand, Haryana adopted an incentive-based approach, along the lines of the Parliamentary Panel's recommendations, in addition to in-situ and ex-situ measures. A financial incentive of ₹1,000/acre for CRM use; ₹4,000/acre for direct seeding of rice; ₹7,000/acre for diversification to alternate crops; and incentives to panchayats for better performance have been put in place.

Punjab and Haryana are reported to have collectively achieved a 90% reduction in stubble burning incidents during paddy harvesting in 2025 in comparison to the same period in 2022 (Lok Sabha starred question No. 18, 1.12.2025). However, this assessment needs to be interpreted with caution, given some issues in measurement.

Measurement problem

Presently, the CREAMS (Consortium for Research on Agroecosystem Monitoring and Modeling from Space) protocol used for measuring stubble burning is built on NASA's MODIS and VIIRS satellites. These are polar satellites that orbit the earth's poles and observe India only at fixed times of the day, from 10:30 am to 1:30 pm. Their sensors are able to capture only active fires and are unable to compute the actual number of fires over a 24-hour period. According to a report by the International Forum for Environment, Sustainability and Technology in 2025, when data from multiple satellites was used to compute the actual land area affected by fire, the reduction was more gradual, at around 30%. A Current Science study in November 2025, led by scientists from ISRO using geostationary satellite observations, showed that farmers have shifted to stubble burning in the evening hours to avoid polar satellites. This study suggested using both polar and geostationary satellite data for an accurate picture of stubble burning.

Conclusion

In conclusion, stubble burning is a complex phenomenon driven by technological, economic and legal factors. The solution should be a judicious mix of the short-term in-situ and ex-situ measures with the medium/long term crop diversification (away from paddy). There needs to be an improvement in the methodology of measurement. Penal provisions are unlikely to be useful as there can be perverse incentives for collusion between farmers and officials, which may lead to 'showing' a reduction, rather than an actual reduction.

(C.S.C.Sekhar is professor of economics, Institute of Economic Growth, Delhi University)