Stubble Burning in India Explained

Every October and November, satellite images of north-western India show clusters of small fires spreading across the plains of Punjab and Haryana, and a grey haze begins to settle over Delhi. Stubble burning is the practice of setting fire to the straw and stalks that remain in a field after the grain has been harvested, so that the land can be cleared quickly for the next crop. In India it is most closely associated with the burning of paddy residue after the kharif rice harvest.

The practice is old and, from the farmer’s point of view, cheap and convenient. But when millions of hectares are burnt within a few weeks, the smoke becomes a major regional air-quality problem and a serious public-health concern. This explainer looks at why farmers burn residue, how the rice-wheat cycle and the combine harvester shaped the practice, its link with Delhi-NCR’s winter smog, the alternatives on offer and the policy response.

Quick Facts

What Is Stubble Burning?

After a crop is harvested, a layer of stems, leaves and roots is left in the field. This is called crop residue, and its stubble is the part of the stem that remains standing above the soil. In many parts of India, farmers use residue for animal fodder, thatching or fuel. Where a lot of residue is generated and there is little demand for it, it is often burnt in the field.

India generates a very large volume of crop residue every year, running into hundreds of millions of tonnes across all crops, with cereals such as rice, wheat and maize, along with sugarcane and cotton, contributing most of it. A significant fraction is surplus to existing uses, and a part of that surplus is burnt. The National Policy for Management of Crop Residue, formulated in 2014, recognised the practice as a problem and called for better management.

Paddy straw versus wheat straw

Wheat straw is valued as animal feed (bhusa) and is mostly collected. Paddy straw is much less useful for this: it is high in silica, less palatable to cattle and bulky. That is why paddy residue, rather than wheat residue, is the central concern in the autumn burning season.

Why Farmers Burn Crop Residue

Farmers rarely burn stubble because they are unaware of the harm. They do so because, under existing conditions, burning is the fastest and cheapest option available to them.

• Time: The window between harvesting paddy and sowing wheat is short, so quick clearance is essential.
• Cost: Removing the straw mechanically or by hand requires labour, machinery and diesel, and the farmer must pay for it. A match costs almost nothing.
• Lack of use: There is limited local demand for paddy straw, and transporting it to buyers is costly.
• Pests and weeds: Many farmers believe that fire destroys pests and weed seeds, even though the benefit is limited.
• Small margins: Marginal and small farmers, who often rent machinery, find the alternatives costly.

The problem is therefore best understood as an economic and logistical one, rather than simply a matter of attitude.

The Rice-Wheat Cycle and the Short Sowing Window

North-western India’s farming system is built on rotating paddy in the kharif season with wheat in the rabi season. Paddy is transplanted in June and July and harvested in late September through October. Wheat must then be sown by about the first half of November for the best yield, because later sowing exposes the crop to the heat of March, which reduces grain filling. This leaves a gap of only two to three weeks, and sometimes less.

How policy shortened the window

Groundwater concerns led states such as Punjab and Haryana to pass laws, notably the Punjab Preservation of Subsoil Water Act, 2009, which delay the transplanting of paddy until mid-June or later, so that the crop benefits more from the monsoon and less from pumped water. This was a sensible measure for conserving groundwater, but it moved the harvest later into October and compressed the already tight gap before wheat sowing. The trade-off between saving groundwater and managing straw is one of the more difficult features of the problem.

Long-duration varieties

Some high-yielding rice varieties take longer to mature and also produce more straw. Agricultural research bodies have been encouraging shorter-duration varieties that mature earlier and leave a longer gap before wheat.

The Combine Harvester Connection

Mechanisation is a major reason the problem grew. Until the 1980s, paddy was harvested mostly by hand, with the plants cut close to the ground. The straw was gathered and used. With rising labour costs and a shortage of workers in the busy season, farmers increasingly adopted combine harvesters, which harvest quickly.

• A combine cuts the crop high and leaves tall stubble standing in the field, often 30 to 40 cm high or more.
• It spreads loose straw in windrows, which obstructs the seed drill of the next crop.
• Conventional wheat seed drills cannot sow through heavy residue, so farmers clear it first, usually by burning.

Combines saved labour and time but shifted the cost of dealing with straw onto the farmer. The Punjab government has in recent years required combines to be fitted with a Super Straw Management System, a device that chops and spreads straw evenly, so that the field can be sown with suitable machinery.

Impact on Delhi-NCR’s Winter Smog

The north-west is also the source region for much of the winter air pollution in Delhi and the National Capital Region. In October and November, winds are often north-westerly, carrying smoke from fires in Punjab and Haryana towards the Indo-Gangetic plain. At the same time, temperatures are falling, wind speeds drop and a temperature inversion traps pollutants near the ground, which produces the dense smog.

A significant but variable contributor

Studies by research institutions and government agencies have estimated that the share of stubble smoke in Delhi’s PM2.5 levels varies considerably from day to day and year to year. On some peak days in the burning season it has been one of the largest contributors, and on others, when winds are unfavourable, it is small. Delhi has its own year-round sources, including vehicle exhaust, road and construction dust, industry, power plants and household burning, and its pollution cannot be attributed to stubble alone. The correct picture is that residue burning adds a severe seasonal spike on top of a baseline of local pollution.

Health, Soil and Environmental Costs

Effects on human health

Smoke from burning residue contains fine particles that penetrate deep into the lungs, along with carbon monoxide and other toxic gases. These aggravate asthma, bronchitis and heart disease, and affect children, the elderly and outdoor workers most severely. The farming communities in the burning areas themselves suffer from the smoke too, and the practice causes accidents on roads when visibility falls and fires spread to neighbouring land.

Effects on the soil

• Burning destroys a large part of the nitrogen, sulphur and organic carbon in the residue, which could otherwise have enriched the soil.
• Intense heat on the topsoil kills beneficial microbes, earthworms and other organisms.
• Soil moisture and organic matter fall over time, increasing the need for fertiliser and irrigation.

Climate effects

Residue fires emit greenhouse gases, such as carbon dioxide, methane and nitrous oxide, as well as black carbon, which absorbs heat and contributes to regional warming.

Alternatives: In-Situ Management

“In-situ” management means handling the residue in the field itself, without removing it. These methods are central to government schemes.

The incorporation of straw into the soil can improve soil structure and organic carbon over time, which gives these methods a long-term agricultural benefit as well as an environmental one.

Alternatives: Ex-Situ Uses of Straw

“Ex-situ” management means removing the straw from the field and putting it to productive use elsewhere. A baler is typically used to compress loose straw into bales that can be transported.

• Biomass power: Straw can be burnt in power plants. The government has also encouraged the co-firing of biomass pellets in coal-based thermal power stations.
• Biofuels: Paddy straw can be converted into compressed biogas (bio-CNG) and into second-generation ethanol, with demonstration plants established in Punjab and Haryana.
• Industrial uses: Straw is used in paperboard, packaging, cardboard, and brick kilns.
• Animal feed and bedding: Treated straw may be used as fodder, and in some places for livestock bedding.
• Mushroom cultivation and composting: Straw is a substrate for growing mushrooms and for making compost.

The main obstacle for ex-situ use is the logistics of collecting, storing and transporting the bulky straw within a very short period, in a supply chain that is still developing. A reliable and fairly priced market for straw is needed before farmers will treat it as a commodity.

Policy and Legal Framework

Several laws and instruments deal with stubble burning. The practice is treated as an offence under the Air (Prevention and Control of Pollution) Act, 1981, and in December 2015 the National Green Tribunal prohibited the burning of crop residue in Punjab, Haryana, Uttar Pradesh, Rajasthan and Delhi, with environmental compensation graded by the size of the landholding. State governments have also used penalties, such as fines, red entries in revenue records and denial of some benefits, though enforcement is difficult and politically sensitive.

Support schemes

• A central sector scheme, launched around 2018, supports in-situ management of crop residue in Punjab, Haryana, Uttar Pradesh and Delhi, with subsidies for machines and for custom hiring centres, so that small farmers can rent equipment.
• The Ministry of Power has issued a policy on biomass utilisation, including mandatory co-firing in thermal power plants.
• The Commission for Air Quality Management in the National Capital Region and Adjoining Areas was set up in 2020 through an ordinance and became a statutory body through an Act in 2021. It co-ordinates action across the states, issues directions and has the power to impose penalties.

Satellite-based monitoring of fire locations by agencies such as ISRO and the Indian Agricultural Research Institute is used to count fire events and to direct enforcement and awareness efforts.

Challenges and the Way Forward

Despite subsidised machinery and awareness campaigns, burning has persisted, and the number of fire events fluctuates from year to year, depending in part on the weather and the timing of the harvest. Several challenges explain why.

• Machines are costly, and small farmers cannot afford them or their fuel, even with subsidies, and a machine used only a few weeks a year is hard to justify.
• Rental markets and custom hiring centres are not always available at the right moment.
• Farmers may not trust that unburnt straw will not cause pests or lower yields.
• Government procurement of paddy and wheat at minimum support prices rewards continued rice-wheat monoculture, which makes the underlying cropping system difficult to change.

Solutions discussed by experts

Many experts favour a package of steps: strong financial incentives for farmers who do not burn, assured purchase of straw by industry, diversification away from paddy to maize, pulses and other crops in parts of Punjab and Haryana, wider adoption of short-duration varieties, and good local logistics for baling and transport. The aim is to make not-burning the economically sensible option for the farmer, rather than relying solely on punishment.

Conclusion

Stubble burning is a problem rooted in farming practice and economics: a fast rice-wheat cycle, mechanised harvesting, groundwater laws and a lack of profitable uses for straw. It has serious consequences for air quality, health and soil, yet it cannot be solved by law alone. Lasting progress will depend on affordable machinery, functioning markets for straw, crop diversification and fair support to the farmers who must bear the cost of change.

Frequently Asked Questions

Why do farmers in Punjab and Haryana burn paddy stubble?

The gap between harvesting paddy and sowing wheat is only a few weeks, and burning is the cheapest and quickest way to clear the field. Combine harvesters leave tall stubble and loose straw, and removing it by other means costs more money and time.

Does stubble burning cause Delhi’s smog?

It is one important contributor but not the only one. In the burning season, smoke carried by north-westerly winds can raise Delhi’s pollution sharply on some days, with the share varying from day to day. Vehicles, dust, industry and other local sources also contribute throughout the year.

What is a Happy Seeder?

The Happy Seeder is a tractor-mounted machine that sows wheat directly through the paddy residue, without burning it. It cuts and lifts the straw, places the seed in the soil, and spreads the straw back over the field as mulch.

What is the Pusa bio-decomposer?

It is a microbial solution developed by the Indian Agricultural Research Institute, which is sprayed on paddy stubble to speed up its decomposition in the soil. This allows farmers to sow the next crop without burning the residue.

Is stubble burning illegal in India?

Yes. The National Green Tribunal banned it in 2015 in several north-western states, and it is an offence under pollution laws, attracting fines graded by landholding. Enforcement has been difficult, so governments also offer machine subsidies and other incentives.

What can be done with paddy straw instead of burning it?

It can be mixed into the soil, used as mulch, baled and sold for biomass power, bio-CNG or second-generation ethanol, used in paperboard and packaging, or used as fodder and as a substrate for mushrooms. Each option needs proper collection and transport arrangements to succeed.

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