Delhi’s winter woes: Why the city turns into a gas chamber every year Explained

As soon as November comes, there is a huge change in the atmosphere of Delhi. Gone are the days of sunny skies and pleasant walks in parks. Instead, every winter, especially after Diwali, a thick layer of smog envelops the city, leaving residents gasping for air. The air quality index (AQI) rises to hazardous levels, with air quality often falling from ‘severe’ to ‘hazardous’ categories.

With the onset of winter, especially during Diwali and the weeks following it, the air quality in Delhi and the National Capital Region (NCR) worsens every year. Every year, the air quality in Delhi-NCR deteriorates during the Diwali and winter seasons due to stubble burning, vehicular emissions and industrial pollution, among other factors. Bursting of firecrackers during Diwali also has a major contribution in the increasing air pollution in the national capital.

The situation becomes particularly severe during the winter months, when the AQI often exceeds 400, indicating ‘hazardous’ air quality.

According to a 2024 study published in Lancet Planetary Health, long-term exposure to air pollution could lead to 1.5 million deaths annually in India.

As per Central Pollution Control Board (CPCB) standards, the AQI scale classifies air quality levels as 0-50 (good), 51-100 (satisfactory), 101-200 (moderate), 201-300 (poor), 301-400 (very poor), and 401-500 (severe).

Why does Delhi become a ‘gas chamber’ every year?

Stubble Burning: After the monsoon season, Farmers in neighboring states like Punjab, Uttar Pradesh and Haryana burn the residue (stubble) of their rice crop To quickly prepare fields for the next crop. Burning of agricultural crop residues or ACR is a major contributor to air pollution in New Delhi.

Vehicle Emissions: The number of vehicles registered in Delhi has increased dramatically over the past few years, and many are older, less efficient models. Vehicle emissions are one of the major sources of air pollution in the city.

Industrial Emissions: All kinds industrial pollutionIndustrial emissions, in particular, along with sulfur dioxide (SO2) and particulate matter, are the major sources of pollution in Delhi.

Construction Dust: Rapid urbanization and infrastructure projects have contributed significantly to this dust pollution in delhiAlong with other major sources. Dust from construction sites and roads causes a significant increase in particulate matter (PM) such as PM 2.5 and PM 10 in Delhi’s air.

Burning Garbage: Burning of garbage, including garbage, contributes to Delhi’s air pollution.