India: Environmental study says vehicles biggest source of particulate air pollution in Delhi

Vehicles have emerged as the biggest contributor to particulate pollution in Delhi. Their real time share increased to more than 50% during the early phase of winter (Oct. 24-Nov. 8), says a study released on Nov. 11 by the Center for Science and Environment (CSE).

The CSE study has analyzed the real-time data on source contribution done by the Decision Support System (DSS) for Air Quality Management of the Indian Institute of Tropical Meteorology (IITM) in Pune.

The other contributors, in descending order, are household pollution, industries, the construction sector, solid waste and road dust.

An additional CSE analysis of the trends in traffic speed in the city — a measure of congestion — during early winter (Oct. 27- Nov. 6) on 15 stretches of key roads shows that traffic congestion is back to pre-pandemic times and correlates with the pollution peaks.

“Clearly, after the closure of all coal-based power plants, expansion of natural gas usage in industry and controls on dirty fuels, vehicles have emerged as the biggest real-time contributor among the local sources of winter pollution in Delhi this year.

“Action on transportation has to gather strong momentum. At the same time, action on waste management, clean energy access to households and dust control must be speeded up,” points out Anumita Roychowdhury, Executive Director of Research and Advocacy at CSE.

The CSE study has analyzed the real-time data on the relative contribution of different pollution sources to Delhi’s air quality. It has accessed data for every alternate hour for the Oct. 24- Nov. 8 period. The pollution sources include transport, industry, construction, waste burning, energy, residential sources, road dust and others.

The analysis makes it clear that vehicular contribution accounts for half or more of the total. This is followed by household pollution ranging between 12.5-13.5%, industry (9.9-13.7%), construction (6.7-7.9%), waste burning and road dust (between 4.6-4.9%, and 3.6-4.1%, respectively). This indicative trend is based on the trends visible every alternate hour during the study period.

The DSS of the IITM is part of the “Air Quality Early Warning System” and provides information on the potential emission sources affecting air quality in Delhi.