According to a study conducted by The Energy and Resources Institute (TERI), the particulate matter 2.5 levels (PM2.5) in Delhi’s air during the winter season would continue to be dangerous despite having reduced by 30 per cent.

In the business as usual scenario, PM2.5 concentrations in winter are expected to fall by 9 per cent, 21 per cent, and 28 per cent in 2022, 2025, and 2030 respectively, when compared to 2019, the base year of the study.

Though the PM2.5 concentrations may fall marginally over the years, the levels will continue to remain significantly above the national standards of 60µg per m³, notes the study titled ‘Cost effectiveness of interventions for control of air pollution in Delhi’, which was published today, on December 9.

The air has suspended particulate matter (PM) of different sizes and many of these are a complex mixture of dust, pollen, soot and smoke and they are hazardous. Of this, PM 2.5 is the smaller kind, with a diameter not more than 2.5 micrometers (fine particles). PM2.5 is considered to have an adverse health impact as it can stay in the air for days or weeks, and is small enough to invade the lung airways.

Vibha Dhawan, Director-General of TERI, was quoted, “Air pollution should be focused as a problem throughout the year not only during the winter season. Stringent actions are needed in the whole airshed to improve air quality in the NCR. Instead of completely banning the essential activities, it is important to switch to the cleaner options.”

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Meanwhile, Anju Goel, co-project investigator and fellow at TERI, said, “Air pollution levels in Delhi are worsened by regional sources which add to the local sources within the city. Airshed-based regional scale air quality controls are required for effective control of air quality in the region”.

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The study estimates the emission and PM2.5 concentration reduction potentials of different policy interventions across sectors such as transport, biomass and industries. It also assesses the health and economic co-benefits of an airshed approach to address air pollution, and calculates direct and associated benefits like an additional economic benefit of Rs 430 billion ($6.2 billion), if regional PM2.5 control strategies are implemented between 2022-2030.

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Some of the major findings of the study

• Transport (23 per cent), industries including power plants (23 per cent), and biomass burning (14 per cent) were the major contributors to prevailing winter time PM2.5 concentrations in Delhi during 2019.
• This study shows that stringent NCR level and airshed level controls which it advocates can bring winter season PM2.5 concentrations in Delhi down to 103-119 µg/m3 (micrograms (one-millionth of a gram) per cubic meter air) and about 83-88 µg/m3, respectively between 2022-2030. This is will be a reduction of 20-27 per cent, and 36-47 per cent with reference to business as usual scenario between 2022-2030.
• Despite reduction of 21 per cent in PM2.5 concentration in a business as usual scenario in the years 2022-2030, mortalities will increase by 7% i.e. 14,400 in 2022 to 15,500 in 2030 in Delhi due to ageing population.
• Out of total 45000 mortalities in Delhi NCR in BAU scenario, around 12,300 mortalities will be avoided in the year 2030 in Delhi NCR if control strategies are implemented at the airshed level over and above the BAU. This will result in additional economic benefits of around Rs. 430 billion.