Delhi has over 10.3 million registered vehicles in the city, which are responsible for 41% of the total pollution load on the capital.  (Pradeep Gaur/Mint)
Delhi has over 10.3 million registered vehicles in the city, which are responsible for 41% of the total pollution load on the capital. (Pradeep Gaur/Mint)

Why is Delhi’s air so toxic?

  • The transport sector is also the main source for PM2.5 emissions, a pollutant which can have disastrous long-term impact of human health
  • With as many as 3,182 industries located across the Delhi-National Capital Region (NCR), industrial pollution adds about 18.6% to the bad air quality

NEW DELHI : As Delhi struggles to cope with one of the biggest health emergencies due to severe levels of air pollution, it has not quite been able to mitigate even the half the problem in last two decades. The level of PM2.5 is on record high, MINT attempts to explain what it is behind this toxic air in country’s capital.

VEHICLES: Delhi has over 10.3 million registered vehicles in the city, which are responsible for 41% of the total pollution load on the capital. The number of vehicles has grown four fold in last two decades, explaining how sources of pollution continue to outperform the mitigation measures. The transport sector is also the main source for PM2.5 emissions, a pollutant which can have disastrous long-term impact of human health.

INDUSTRIES: With as many as 3,182 industries located across the Delhi-National Capital Region (NCR), industrial pollution adds about 18.6% to the bad air quality. Emission of the order of 200-1000 ton/yr is found over industrial zone next to major roads. All fuel based and coal industries are ordered shut as part of emergency plan.

POWER PLANTS: There are four thermal power plants in Delhi, two are coal-based including the Badarpar Power Plant and two are gas based. Significant action was achieved after closing down of Badarpur Power plant in October last year.

BRICK KILNS/CONSTRUCTION ACTIVITIES: Outskirts of NCT have roughly 360 brick kilns majorly scattered in Jhajjar, Faridabad and Ghaziabad region. Since, their peak business month starts from December to June, the emissions from these brick kiln also rise during the winter months. This is why stopping construction activities, including hot mix plants, stone crushers, brick kilns is among the first emergency measure taken post Diwali.

STUBBLE BURNING: Though, not the primary cause of pollution, air quality in the capital worsens after stubble burning begins in the neighbouring northern states October onwards. The problem is only expected to exacerbate with shortening of gap between Kharif harvesting and sowing of Rabi crops, due to delayed retreat of monsoon. In such cases, farmers would have less time to prepare the fields for next sowing.

TOPOGRAPHY: Located north-west of the Central plains and southwest of the Himalayan region, Delhi suffers from a major geographical disadvantage which enables transportation of pollutants towards it and facilitates its accumulation. The wind drops post the retreat of monsoon, and changes direction soon after, so whatever pollutants enters its boundary, it remains trapped. This explains why windblown dust is responsible for nearly 21.5% of the pollution load.

MUNICIPAL SOLID WASTE: Approx. 8370 tonnes of Municipal solid waste is generated in Delhi every day and on an average 3,240 tonnes per day is being incinerated in quantity Solid Waste Treatment plants. Both thermal power stations and waste management plants are some of other highly emitted zone, contributing to 3.9% of the pollution load.

WEATHER: Delhi‘s air is toxic all year round, it just becomes more visible in winters when the city is covered by smog. Why the situation worsens in winter is because the winds disappear and mixing height of pollutants gets lowered, which leads to haze. This year, late withdrawal of monsoon also favoured rise in pollution. The situation aggravates as temperatures lower November onwards.

Close