CAQM revisits study: Vehicles, dust, industries lead Delhi-NCR pollution

Facing scrutiny from the Supreme Court, the Commission for Air Quality Monitoring (CAQM) is revisiting the IIT Kanpur-TERI report on air pollution in Delhi-NCR, which will be discussed in the coming days.

According to sources, the High Resolution Multi Pollutants Emissions Inventory of National Capital Region (NCR) reveals variations in pollution sources across Delhi and NCR, according to a report by The Economic Times.

In Delhi, road dust and transportation are the primary sources of PM10 and PM2.5 pollutants, while industrial emissions dominate in the NCR region. Stubble burning contributes 7-10 per cent to PM10 and PM2.5 levels in NCR. The 2013 IIT Kanpur study on PM2.5 and PM10 source apportionment indicated that road dust accounted for 56 per cent of PM10 and 38 per cent of PM2.5, while vehicular emissions contributed 9 per cent and 20 per cent, respectively.

J-K Assembly elections: Over 11% polling recorded till 9 am in third phase

Road dust in Delhi

The report also found road dust to be responsible for 42 per cent of PM10, with transportation contributing 25 per cent. Ongoing construction in Delhi adds 15 per cent to particulate matter levels, while vehicle exhaust accounts for 47 per cent of PM2.5 emissions. In terms of sulfur dioxide (SO2) and nitrogen oxides (NOx), transport contributes 41 per cent and 78 per cent of emissions, respectively.

Two-wheelers contribute 31 per cent of PM2.5 and PM10 in the NCR, followed by three-wheelers (28 per cent), trucks (18 per cent), and buses (7 per cent). Buses emit 34 per cent of NOx in the region, with two-wheelers and trucks following at 20 per cent and 10 per cent, respectively.

While road dust is the predominant contributor in Delhi, it accounts for only 20 per cent of PM2.5. Data from 2021-22 shows that power plants contribute 8 per cent, diesel generators 4 per cent, and residential sources 5 per cent, the report said.

Agricultural residue burning

In the NCR areas of Uttar Pradesh, Punjab, Haryana, and Rajasthan, industries, stone crushers, and agricultural residue burning are the main pollution sources. However, substantial measures have been taken since 2022, particularly regarding coal-based power plants, which may have reduced pollution levels.

The 2021-22 data also shows that industrial emissions contribute 41 per cent of PM10 in NCR, with 22 per cent from stone crushers and 12 per cent from road dust, the report stated.

For PM2.5 in NCR, industry leads at 44 per cent, followed by stone crushers at 19 per cent. Agricultural burning accounts for up to 10 per cent, similar to the 9 per cent contribution from the transportation sector.

The report quoted experts as saying that efforts to mitigate road dust are showing progress. However, vehicular pollution remains a challenge. The vehicle population in Delhi has grown from 3 million in 1998 to over 12 million in 2019. While the introduction of BS VI emission standards is a significant improvement, their full impact will only be seen by 2027 when the majority of vehicles comply with these norms, the report said.