Come October–November and winter, the media once again sensationalises the narrative of Delhi turning into a “Gas Chamber.” In retrospect, this recurring alarmism amounts more to fraud-mongering than informed public discourse.
Neither pseudo-intellectuals (across sections of the media and climate “experts”) nor political leaders have ever seriously discussed the specific annual winter meteorological phenomenon that lies at the root of air pollution—not just in Delhi, but across the entire Indo-Gangetic Plain.
Nature unleashes its fury every winter. Delhi’s air pollution is severely aggravated by specific meteorological conditions that transform otherwise consistent local emissions into a hazardous “toxic cocktail.”
Ipso facto, while the city’s air quality remains sub-optimal throughout the year, winter climate conditions act like a “lid,” trapping pollutants close to the ground.
The media dismally fails to explain the effect of temperature inversion during winter. In this phenomenon, a layer of warm air settles above cooler air near the surface. This “lid” prevents the natural vertical rise and dispersion of pollutants, forcing them to accumulate at breathing levels.
As a result, the atmospheric “mixing height”—the vertical space available for pollutants to disperse—shrinks from about 1 km in summer to just a few hundred metres in winter. Stagnant winds further fail to move pollutants horizontally out of the city.
To compound the problem, high humidity and fog create dense smog (smoke + fog), which persists longer in cold conditions. Unlike the monsoon season, which “washes out” pollutants through wet deposition, the dry winter months lack any natural cleansing mechanism.
While serving in Punjab in early 1972, I personally experienced the adverse effects of “air pollution” due to surface inversion, compounded by fog/smog and dust storms known as “Loo.” Fog or smog clouds would often drift in from the Pakistan side as well. Airflow patterns from Afghanistan and Pakistan pick up emissions as they move over the densely urbanised regions of Punjab and Haryana.
The problem—even among scientists—is the lack of holistic analysis of air pollution in the Indo-Gangetic Plain. Most importantly, people must first understand Nature’s phenomena.
One cannot fight against Nature’s seasonal visitations, such as the effects of temperature inversions.
Since winter nights are longer, surface inversions are stronger and more frequent. Calm winds, clear skies, and long nights favour the development of strong surface inversions. Warm air over cooler air suppresses vertical mixing and traps cooler air at the surface.
Once the sun sets, the ground loses heat rapidly, cooling the air in contact with it. This leads to cooling of near-surface air at night, forming surface inversions. During daylight hours, these inversions normally weaken and disappear as the sun warms the Earth’s surface—usually after 9 or even 10 a.m.
FACT: Delhi is situated in the landlocked Indo-Gangetic Plain, bordered by the Himalayas to the north and the Aravalli Hills to the southwest. These natural barriers restrict air movement, trapping regional pollutants, including smoke from stubble burning. In late 2024 and 2025, climate models indicated that La Niña conditions often lead to colder winters in North India, worsening pollutant trapping. However, La Niña can also marginally increase wind speeds, occasionally offering brief relief compared to the more stagnant El Niño patterns.
While weather traps the air, human activity provides the toxins. During winter, vehicles and industries contribute 85–94% of the PM2.5 load, as emissions are no longer dispersed by summer heat.
There is also increased biomass burning (wood, coal, waste) for heating, which can account for up to 26% of winter particulate matter. Winter nights further provide ideal conditions for chemical reactions between gases such as ammonia and sulphur dioxide, forming new fine particles and increasing smog density.
Finally, hay/stubble burning adds fuel to the fire. As per media reports, around 20% of Delhi’s air pollution is attributed to stubble burning from neighbouring states. But what about the remaining 80%?
There are exhaustive studies on air pollution identifying the main sources:
vehicle exhaust emissions (over 12 million vehicles); heavy industries such as power generation, including the Badarpur Thermal Plant contributing 80–90% of particulate pollution; small-scale industries like brick kilns; suspended road dust from vehicles and construction; wood-burning fires; cow-dung cake combustion; open waste burning (Bhalswa landfill fires); fuel combustion for cooking, lighting, and heating; heavy-metal-rich firecrackers; and more.
Add to these other contributors: human emissions due to NCR population growth (from 17 lakh in 1951 to over 715 lakhs by 2025, including CO₂ from respiration); ammonia emissions from agriculture; insecticides, pesticides, and fertilisers; carbon dioxide emissions from reduced green cover; domestic use of air conditioners and refrigerators; methane released by cattle; and pre-monsoon dust storms.
Delhi generates approximately 11,300–13,000 tonnes of municipal solid waste (MSW) daily as of 2025, much of which ends up being burned at three landfills—Ghazipur (still active), Bhalswa (commissioned in 1994, declared exhausted in 2006 yet still receiving waste), and Okhla—adding significantly to particulate pollution.
Proposals for waste-management infrastructure—especially waste segregation, recycling, and utilisation of large parks for composting and bio-methanation of wet waste (about 200 tonnes per day for every five lakh population)—remain unimplemented in Delhi.
From April–May and October–November each year, farmers—mainly in Punjab and Haryana—burn an estimated 35 million tonnes of crop residue. The smoke produces a toxic cloud over Delhi, triggering annual air-pollution emergencies.
Although alternatives like the Indian-manufactured Happy Seeder, which shreds and spreads crop residue back into fields, are available, farmers cite high costs as a deterrent. Indigenous machinery, such as hay balers costing between ₹2–11 lakh, can cut, collect, and compress crop residue into compact bales.
Ipso facto, stubble burning is nothing short of burning money. Hay or stubble—grass, legumes, and other herbaceous plants—can be profitably used as animal fodder, especially for cattle, goats, sheep, and horses. Ironically, media reports frequently highlight animal distress in drought-affected areas, while urban animals are seen consuming plastic and paper.
Another high-value use of stubble is organic composting, through aerobic, anaerobic (not recommended due to odour), or efficient windrow methods.
Municipal waste can similarly be converted into compost and even energy.
Waste-to-Energy (WtE) or Energy-from-Waste (EfW) technologies generate heat or electricity from waste, simultaneously addressing disposal and energy generation.
The NDA Government could announce 50% subsidies for balers and Happy Seeders, enforce a strict ban on waste burning, and promote alternative waste utilisation.
In sum, smog and air-pollution levels can only be addressed through a holistic, cooperative, and constructive approach—involving the Central Government and the states of Punjab, Haryana, Uttar Pradesh, Rajasthan, and Delhi, and even at a bilateral level with Pakistan. Otherwise, this will remain a recurring health hazard, claiming over 10,000 lives annually, while political blame games and media sensationalism continue with utter disregard for human life.
Policies and strategies to mitigate pollution must not only be formulated but also implemented effectively, particularly concerning construction activity regulation and uncontrolled vehicle growth.
