Air pollution: Delhi's unique conundrum | The Issue

There’s few cliches left to describe Delhi pollution that have not been used before – something about smoking 50 cigarettes a day, Delhi resembling a post-apocalyptic wasteland, not being able to see even 5 feet away. The descriptors we use don’t change, because the pollution menace unfortunately, also does not change.

Why does Delhi then face such extreme pollution, that renders it a hazard for the close to 2.9 crore people living in and around it? It’s an amalgamation of several different factors that our National Capital unfortunately just has to deal with. And all of these reasons collectively add to the problem of pollution in the capital around a 2-month window of toxic AQI.

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One of the foremost reasons touted to be behind Delhi’s pollution woes is stubble burning – a problem that may have been exacerbated in attempts to curb another climate adversity.
Punjab and Haryana, surrounding Delhi, are key agricultural states. Farmers here grow rice, and the cultivation of rice requires large amounts of water. This can lead to severe depletion of ground water. In order to curb this problem, in 2009 the government passed The Preservation of Subsoil Water Act. This act bans paddy planting before mid-June at which point rains will replenish the ground water levels.

Because paddy can’t be planted till mid-June, harvesting of crops is pushed to late in the year, leaving farmers with less time to prepare their fields for the next winter cycle of crops. Lesser time means that farmers have to rely on the quickest and cheapest method of clearing their fields – which unfortunately is stubble burning.

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What’s concerning for this year especially is that with a prolonged spell of rains delaying paddy harvesting in some regions of Punjab, farmers are more likely to burn stubble to make up for the lost time and quickly prepare their fields for the next crop, experts say.

In 2021, Punjab had reported 71,304 farm fires between September 15 and November 30 and 83,002 farm fires in the corresponding period in 2020.

Smoke clouds from Punjab and Haryana travel to Delhi – and the topography of the region does not help combat the problem. With the Himalayas forming a huge barrier to the north, the smog follows a path through the plains to the bottom of the mountain range. The air begins to accumulate in the region and is unable to escape.

Since hot air rises and cool air settles, owing to the high mountain range and cooler winter air, the smog is unable to rise, keeping it trapped within the plains – forming a dome over the city of which the first layer is hot lowland air, the second is cold mountain air, and the third is stubble burning smoke mixed with urban pollution.

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India’s capital is already the most populated city in the world and some estimates say Delhi could be the world’s most populous city by 2028. More people mean more vehicles on the streets, more household pollution and more construction activities. The main pollutant in Delhi’s air right now is PM 2.5, and sources of PM 2.5 can be both internal and external.

According to a recent study conducted by Centre for Science and Environment, vehicular emissions contribute the highest share to Delhi’s PM 2.5 levels at nearly 50%. The contribution of household pollution has been 12.5%-13.5%, industry has been 9.9%- 13.7%, construction at 6.7%-7.9%, that of waste burning has stood between 4.6%-4.9%, and the contribution of road dust has been 3.6%-4.1%.

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One cannot talk about pollution in Delhi without mentioning the elephant in the room – crackers at Diwali. With the firecracker ban going up in smoke every year, quite literally: the National capital chokes on a cocktail of noxious chemicals after the festival of lights every year.

It’s not like the air in Delhi is good all year round and sees just one very brief period of pollution. Between 2016 and 2021 – Delhi saw only 17 good air days and it tops every list for the most polluted cities in the world.

Several factors that are tough to balance may contribute to the brief, hazardous toxic spike every year – but with clean air elusive for the millions living in Delhi, coming up with a solution to this problem becomes more critical with every passing minute.