Assessing the Scale of Biomass Burning: An In-Depth Look at India’s Agriculture

Every year, as the harvest season unfolds across India’s northern plains, millions of farmers face a familiar dilemma: mountains of leftover crop stalks and nowhere practical to put them. The fastest and cheapest solution has remained the same for decades – set them on fire. What results is one of the most large-scale, recurring episodes of agricultural biomass burning in the world, with consequences that stretch from the fields of Punjab all the way to the lungs of Delhi’s 33 million residents. Understanding the extent and intensity of this burning – the volumes of residue involved, when it peaks, and what it does to air quality – is key to grasping why this is far more than a local farming issue.

Agricultural residues in India: the sheer scale of the problem
Punjab and Haryana: ground zero for crop residue burning
Seasonal trends in burning: two peaks, one annual crisis
Impact on Delhi and NCR air quality
Global comparisons: India in context
Why this burning continues despite the costs

Agricultural residues in India: the sheer scale of the problem

India generates an average of 500 million tonnes of crop residue annually. Of the surplus residue – material left over after uses such as fodder and fuel – approximately 92 million tonnes are burned in fields each year. Rice and wheat together account for nearly 70% of all crop residues generated in the country, a direct consequence of the rice-wheat cropping system that dominates India’s agricultural heartland.

Among all crops, rice straw is the single largest contributor to burning, accounting for roughly 43% of total crop residue burned, followed by wheat at around 21% and sugarcane at 19%. The fraction of paddy residue actually burned ranges from 8% to 80% across different states – and in Punjab, Haryana, and Himachal Pradesh, that figure climbs to 80%, largely driven by the use of combine harvesters that leave behind large volumes of straw.

Punjab and Haryana: ground zero for crop residue burning

Punjab is often described as India’s granary, and the numbers back that up. With the rice-wheat system covering at least 80% of Punjab’s gross cropped area, and Punjab alone contributing around 27% of India’s rice and 37% of its wheat to the national stock – despite being just 1.5% of the country’s land area – the scale of residue generated here is enormous. Punjab and Uttar Pradesh consistently rank as the top two states for total crop residue burned, with Punjab producing approximately 21.32 million tonnes of burned cereal residue annually and Haryana contributing a further 9.18 million tonnes.

About 2 million farms across Punjab and Haryana participate in some form of residue burning each season. According to the Indian Agricultural Research Institute, around 14 million out of the 22 million tonnes of rice stubble generated in India is set alight every year, with Punjab and Haryana together accounting for 48% of that burned total. The primary drivers are economic and logistical: burning is cheap, fast, and requires no equipment. Farmers have a narrow window of just a few weeks between the rice harvest and the next wheat sowing, making the slower alternatives – mechanical incorporation, composting, or off-farm use – difficult to adopt without subsidies or external support.

Seasonal trends in burning: two peaks, one annual crisis

India’s agricultural biomass burning follows a clear two-season pattern. The post-monsoon or kharif season runs through October and November, when the rice crop is harvested across Punjab and Haryana. Paddy is typically reaped between the first and last weeks of October, with burning beginning almost immediately afterward. Farmers must clear fields and prepare for wheat sowing, which runs from the first week of November to mid-December, leaving a gap of only a few weeks. This season generates the most intense burning events and the worst associated air pollution.

The second burning peak, the pre-monsoon or rabi season, occurs in April and May following the wheat harvest. While wheat residue burning is less intense than rice straw burning in terms of smoke output, it is still significant. Research tracking farmers across two consecutive seasons in Haryana found that farmers who burned rice residue were 15 to 21 percent more likely to also burn wheat residue – suggesting that burning behavior compounds across crops and seasons rather than being isolated events.

The timing of burning matters enormously for air quality outcomes. Fires typically peak during afternoon hours when temperatures are highest, and the smoke rises and disperses with stronger daytime winds. Ironically, this means that burning earlier in the morning – before winds pick up – could actually worsen immediate local exposure, while afternoon burning disperses smoke more widely downwind toward urban centers. Research from MIT and collaborators found that shifting burning to two hours earlier in the day in Punjab alone could prevent up to 9,600 premature deaths annually.

Impact on Delhi and NCR air quality

Delhi’s air quality deteriorates sharply every October, and crop residue burning in Punjab and Haryana plays a well-documented role. During the crop-burning season, the practice can account for up to 45% of Delhi’s pollution according to government meteorologists, though researchers note the contribution varies significantly by day and meteorological conditions. Studies using satellite data, chemical transport models, and ground sensor networks have estimated that fire emissions from Punjab contributed around 14-20% of the overall PM2.5 load over Delhi-NCR during the October-November burning period.

The consequences are stark. In November 2017, the so-called “Great Smog of Delhi” pushed PM2.5 and PM10 levels to 999 μg/m³, against safe limits of 60 and 100 μg/m³ respectively – levels nearly 10 to 16 times above what is considered safe. In November 2024, Delhi’s AQI reading briefly hit 1,200, momentarily making it the most polluted city on the planet. During peak burning months, PM10 and PM2.5 concentrations regularly exceed India’s National Ambient Air Quality Standards by 2 to 3 times.

What makes this pollution so damaging is its chemistry and seasonality. Biomass smoke releases fine particulate matter (PM2.5), carbon monoxide, methane, volatile organic compounds, and carcinogenic polycyclic aromatic hydrocarbons. These particles are light enough to remain suspended in the air for days and travel hundreds of kilometres. In October and November, cooler temperatures and slower winds trap pollution near ground level, compounding the health impact. The northwest-to-southeast wind pattern characteristic of post-monsoon India carries smoke from Punjab and Haryana directly toward Delhi and the broader NCR.

A major study in Nature Communications covering the period 2003-2019 estimated that agricultural residue burning caused between 44,000 and 98,000 premature deaths annually across India from PM2.5 exposure. Punjab, Haryana, and Uttar Pradesh together contributed 67-90% of these deaths. Six districts within Punjab alone accounted for 40% of India’s total annual air quality impacts from residue burning – a remarkable concentration of harm from a geographically small area.

Global comparisons: India in context

India’s scale of agricultural biomass burning is significant globally, but it is part of a much wider pattern. Globally, agricultural waste burning contributes around 23% of total biomass burning emissions worldwide, with savannah fires accounting for the largest share at roughly 43%. India’s burning is distinctive in its intensity, frequency, and proximity to massive urban populations – characteristics that amplify its health consequences compared to burning in less densely populated regions.

China faces a directly comparable problem. The North China Plain – particularly provinces such as Shandong, Henan, and Anhui – experiences intense crop residue burning during harvest seasons, and burning of wheat and corn residue has been identified as a major contributor to high PM2.5 concentrations in Beijing. The number of agricultural fires in China grew threefold between 2003 and 2014, driven by the same economic logic as in India: as rural households shifted away from using straw as fuel, field burning became the default disposal method.

In Brazil, sugarcane burning is the principal form of agricultural biomass burning, concentrated in the state of São Paulo. Research has identified it as the main source of PM2.5 in several Brazilian cities, and biomass burning emissions during Brazil’s 2019 fire season were estimated to cause 10% of all PM-related deaths nationally. Sub-Saharan Africa holds the largest share of global biomass burning by area, driven primarily by savannah fires and shifting cultivation – with approximately 75% of global infant deaths attributable to biomass burning exposure occurring on the African continent. The World Bank notes that among the top agricultural burning nations, Mexico and Tanzania stand out for burning intensity per hectare, followed by Brazil, the United States, and Nigeria.

What distinguishes India’s situation is not simply the volume of burning, but the combination of high burning intensity, dense downwind populations, and a compressed seasonal window that produces acute pollution spikes rather than diffuse, year-round exposure. Punjab’s six most intensive burning districts, each with relatively high crop residue output and large downwind populations, are responsible for a disproportionate share of health damage not just within India but in terms of global agricultural fire impacts per unit area.

Why this burning continues despite the costs

With bans in place, subsidies offered for alternative machinery, and Supreme Court interventions on record, stubble burning continues because the economic incentives remain misaligned. Burning is essentially free and takes hours; machine incorporation or off-farm residue use costs money and time that farmers – operating on thin margins – cannot easily absorb. The Ministry of Agriculture attributes the rise in on-farm burning to a shortage of human labour, as mechanized combine harvesters replaced the manual harvesting that once left residues in more manageable forms. A policy environment that incentivizes high paddy production through price supports, combined with laws that restrict early sowing (and thus compress the planting window), has effectively locked the system into burning as the rational choice for individual farmers, even as the collective cost to public health is enormous.

What do you think? Given that individual farmers face real economic pressures to burn – while the health costs are borne by millions of others downwind – how should governments balance enforcement with financial support to make alternatives genuinely accessible? And as countries like China and Brazil face nearly identical challenges with agricultural residue burning, what does this tell us about the limits of bans alone as a policy tool?

References

PDF 📄

Table of Contents

Agricultural residues in India: the sheer scale of the problem 🔗

Punjab and Haryana: ground zero for crop residue burning 🔗

Seasonal trends in burning: two peaks, one annual crisis 🔗

Impact on Delhi and NCR air quality 🔗

Global comparisons: India in context 🔗

Why this burning continues despite the costs 🔗