Today's Paper

Cars are not the biggest polluters in Delhi

Delhi is gearing up for the odd-even scheme to check vehicular pollution, but road dust, burning of biomass and municipal solid waste, and industrial stacks contribute a far greater share of the city's air pollution, according to a study by the Indian Institute of Technology-Kanpur.

The draft report found that particulate matter (PM) pollution from road dust, from various sources, was the highest in both categories: PM10 and PM2.5. Road dust contributed 56% of all PM10 pollution while it was 38% for PM2.5.

According to the same report, vehicular pollution from trucks, cars and two vehicles made up 9%-20% of the particulate matter pollution depending on whether it was summer or winter.Other key contributors to pollution are burning of bio-mass (17%-26%), municipal solid waste (6%-7%) and secondary particulate matter that could range from 25%-30%, according to the report.

The study to determine various sources of pollution in the Capital was commissioned by the Delhi government in 2013 and the draft was submitted to Environment Department in late November.

A separate estimate by the Indian Institute of Tropical Meteorology, Pune has different numbers but still ranks dust as the major contributor—52%--to the city’s PM10 load.

“In most other cities, road dust plays a much more important role and as industries develop, vehicles increase the relative share of dust begins to decrease,” said Prashant Goswami, of the Council of Scientific Industrial Research, who has modelled weather and pollution trends across cities, “Factors such as the soil quality and wind profiles begin to play an important role.”

Before PM2.5 became the focus of attention—for its role in lodging itself in the lungs and being a key component of diesel emissions—dust was the key villain for a long time. For one, dust is a generic term for a vast mix of metals –silicone, aluminium, titanium, manganese, copper, barium, antimony, selenium and zinc.

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