Vehicles behind lion’s share of particulate pollution in Capital
NEW DELHI: Among the local sources of pollution in Delhi, vehicles have emerged as the biggest contributor to particulate pollution, with their real-time share touching more than 50% during the early phase of winter, between October 24 and November 8, 2021, an analysis released by the Centre for Science and Environment (CSE) on Thursday showed.
The analysis, based on data generated by the Indian Institute of Tropical Meteorology, showed that after traffic, household sources, industries and construction were the other leading sources of pollution in the Capital.
Particulate matter is the general term for inhalable particles in the air such as aerosols, smoke, fumes, dust, ash and pollen.
During the period from October 24 to November 8, which also saw pre-Diwali rush and snarls, the CSE said traffic speeds fell noticeably and congestion touched the pre-pandemic levels. The CSE said it accessed data for every alternate hour, for the period between October 24 and November 8, to arrive at the conclusion that vehicular emissions contributed over 50% to the particulate pollution, followed by household pollution sources, whose share ranged between 12.5-13.5%.
This was followed by industries (9.9-13.7%), construction sources (6.7-7.9%), waste burning (4.6-4.9%) and road dust, which contributed between 3.6-4.1% to the total pollution load during the studied period.
“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 all 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 expedited,” says Anumita Roychowdhury, executive director, research and advocacy, CSE.
The Delhi Pollution Control Committee (DPCC) data for this period shows while the hourly average PM2.5 concentration touched nearly 2,000 micrograms per cubic metre (µg/m3) on Diwali day, stations prior to Diwali were recording peak pollution levels of 500-600µg/m3 during the day — readings that are 10 times the national-safe limit of 60µg/m3. Data from a station such as the one in RK Puram, an area that sees heavy traffic during the day, showed a spike in pollution between 8am and 9am.
However, the biggest spike in pollution during the day occurred after 7pm, as the temperatures dropped. Levels at the station ranged between 200-400 µg/m3 through the day, according to the data.
CSE said while the analysis only focuses on internal sources of pollution, the contribution from stubble (biomass) burning was low until November 3 and only picked up significantly from November 5. It found that while contribution from sources of pollution in NCR dominated between November 2 and 6, accounting for a total pollution share as high as 70-80%, its share declined after Diwali and Delhi’s own sources of pollution increased, along with stubble burning.