Hyderabad: Every year, with the onset of winter, Delhi and the northern states of India get sheathed in a blanket of smog. The reason is common knowledge: the burning of stubble or the residue of paddy crops.
Yet in 2025, even with stubble burning incidents dropping in Punjab and Haryana, Delhi’s air quality worsened, revealing a more complex pollution story.
What is the extent of stubble burning in South India?
But here’s a puzzle: Why doesn’t the southern half of India, which grows paddy extensively and consumes far more rice than the north, choke on similar smog?
South India does not suffer the same pollution crisis as Punjab, Haryana and Western Uttar Pradesh because farmers in the southern states simply do not burn stubble at the same scale. While less than 1 per cent of southern farmers engage in stubble burning, it remains a widespread practice in the north each winter.
This brings us to the central question: Why is stubble-burning rampant in the north but not in the south, despite the south’s deep cultural and dietary dependence on rice?
The answer lies in an intricate web of factors: the Green Revolution, government regulations designed to save groundwater, climatic patterns, crop cycles, dietary habits and even the varieties of rice cultivated in different regions.
The Green Revolution’s unintended legacy
The Green Revolution, launched in the 1970s in Punjab and Haryana, fundamentally transformed India’s agricultural landscape. These two states shifted from traditional crops, maize, millets, oilseeds and pulses, to an intensive wheat-paddy cultivation cycle.
Crucially, the region had not historically grown paddy. The government-sponsored wheat-paddy cycle was an engineered transformation, not an organic evolution of local farming practices.
This distinction would prove critical.
Rice cultivation is extraordinarily water-intensive; producing just one kilogram of rice requires an average of 1,432 litres of water. Initially, farmers relied on shallow wells for irrigation. But as these wells depleted, tube wells powered by free government electricity became ubiquitous among affluent farmers.
Then came the 1993 introduction of Govinda, a new hybrid rice variety that matured in just 60 days. This allowed farmers to sow paddy twice during the kharif season (April to October), doubling their income. With Minimum Support Prices (MSP) guaranteed by both governments, farmers enthusiastically adopted this intensive cultivation pattern.
The groundwater crisis and its solution
The intensification had severe consequences. Groundwater in the region began depleting at alarming rates. The latest report by the Central Groundwater Board reveals that most districts in Punjab have overexploited groundwater reserves, with some districts reaching critical levels.
When agricultural scientists recognised the severity of this crisis, they urged the Punjab government to act. The result was the Punjab Preservation of Subsoil Water Act of 2009, designed to conserve groundwater by mandatorily delaying paddy transplanting until after June 10, when the most severe phase of evapotranspiration, the transfer of water from land to atmosphere, is over.
Farmers were forbidden from sowing paddy before May 10 and transplanting before June 10. Haryana passed similar legislation.
This well-intentioned law had an unintended consequence: it pushed the harvesting season from late September to the end of October and early November. With wheat cultivation needing to begin during favourable winter temperatures, farmers were left with virtually no time between harvesting paddy and sowing wheat.
A government remedy to conserve groundwater inadvertently forced farmers into burning stubble.
Enter stubble-burning and winter smog
“The stubble can decompose on its own, but for that, the farmer has to leave it in the field for at least a month,” explains GV Ramanjaneyulu, executive director at the Centre for Sustainable Agriculture in Hyderabad. “But since they want to start wheat cultivation quickly, farmers choose to burn the stubble.”
This practice peaks between September and November, precisely when wintry conditions, moist air and largely inactive wind systems begin to set in. The particulate matter and gases from burning paddy stubble stay suspended in the atmosphere and get carried toward Delhi when north-westerly winds blow.
Recent data confirms this pattern persists, though the equation has evolved.
In 2024, despite a 75 per cent decline in farm fires in Punjab, Delhi’s annual PM2.5 levels rose by 3.4 per cent. Local sources—particularly vehicular emissions, which account for over half of Delhi’s PM2.5 pollution have emerged as equally significant contributors. As one researcher noted, “Delhi cannot hide behind the smoke screen of farm fires anymore.”
Why South India is different: Rice culture without the smoke
The situation in southern India presents a stark contrast, rooted in fundamentally different agricultural rhythms, dietary patterns and crop choices.
1. No sowing restrictions: Southern states face no government mandates on when to sow paddy. “We start as soon as the monsoon starts here,” says Ramanjaneyulu. In Kerala, monsoons begin in late May or early June and reach Telangana by early to mid-June. Crops are harvested by late September or early October, giving farmers ample time to let stubble degrade naturally in the fields.
2. Different crop cycles: Unlike the north’s wheat-paddy cycle, southern farmers grow pulses, millets, and other rabi crops after paddy. There’s no pressure to rush into wheat cultivation.
“When you leave the stubble in the field and cultivate wheat, there are chances of confusing the two, and so the stubble has to be destroyed completely,” Ramanjaneyulu explains. “Here in South India, we don’t have to worry about paddy getting mixed with pulses; the plants can be differentiated easily.”
3. Cattle fodder: Southern farmers use stubble as cattle fodder, adding economic value to what northern farmers see as agricultural waste.
4. Climate advantage: South India’s higher temperatures prevent fog formation, and winds blow more consistently, preventing pollutants from accumulating in the atmosphere.
The rice-eating paradox
Here’s where the dietary dimension becomes fascinating. Southern India consumes significantly more rice than the north; in fact, rice is the overwhelming staple throughout the south, east, and northeast of India.
According to National Sample Survey data, rice consumption is highest in these regions. Manipur, for instance, lives almost solely on rice. Southern states like Tamil Nadu, Kerala, Karnataka, Telangana and Andhra Pradesh have rice as their primary staple, with white rice being the top choice for 76 per cent of respondents in consumer surveys, particularly pronounced in South India.
Meanwhile, northern states like Punjab, Haryana and Rajasthan, where stubble burning is endemic, actually prefer wheat. Rajasthan’s rice consumption is negligible. Even in Punjab and Haryana, the wheat-roti culture dominates. Bihar presents an interesting middle ground, consuming rice and wheat in nearly equal quantities.
This creates a remarkable irony: The regions that eat the most rice don’t produce the pollution crisis, while the regions that historically preferred wheat and adopted rice cultivation as a Green Revolution policy intervention are now choking on the consequences.
South India's rice cultivation evolved organically over millennia, shaped by monsoon patterns, soil types, and cultural preferences. Rice is not merely a crop in South India—it’s embedded in the cultural, culinary and agricultural fabric. This deep integration has created farming systems that work in harmony with regional climatic conditions.
