Winter woes: Share of external sources in PM2.5 at 22% in first 10 days of Dec
New Delhi: An analysis by System of Air Quality and Weather Forecasting and Research (SAFAR), the forecasting body under the Union ministry of earth sciences, has determined that the average proportion of PM2.5 from external sources within 200km of Delhi was 22% in December 1-10. With non-local pollutants an important factor in overall winter pollution, experts felt strong action was needed to curb emissions in the airshed for better air in the city. Gufran Beig, SAFAR’s founder-project director, said, “The contribution of external sources to Delhi’s pollution varies from season to season and day to day. The average share of external sources to the city’s PM2.5 in the winter season is 15-30% and may reach 35% on a particular day.” He added, “In contrast to the winter season, the wind speed and mixing layer height remain high in summer, leading to dispersion of pollutants and in monsoons, rain settles down pollutants. In winter, however, local conditions cause stagnation of particles.” SAFAR apportioned the local pollution sources between December 1-10 as 36% to vehicles and transport, 17% to dust, 14% industries, 2% fuel burning and 8%, other pollutant sources. The share of stubble burning in this period was just 1%. Experts said it was not enough just to focus on Delhi’s own generation of pollutants. Anumita Roy Chowdhury, executive director, research and advocacy, Centre for Science and Environment, said, “With substantial external pollution, a regional action plan is a must for controlling emissions in Delhi and the 24 NCR districts. The plan should be multi-sectoral, targeting the industry hotspots, vehicles, dust, power plants and waste management.” The Decision Support System of the Indian Institute of Tropical Meteorology, Pune, said the emission from 19 neighbouring districts constituted from nil to 10% of the PM2.5 in Delhi’s air on any day. That is why, said Anju Goel, fellow, earth science and climate change, The Energy and Resources Institute, action had to be taken at the airshed level. “The focus should be on shifting coal-based power plants to cleaner fuels, eliminating biomass and fuel burning and ensuring compliance of construction guidelines,” Goel said. Tanushree Ganguly, programme lead, Council on Energy, Environment and Water, noted that SAFAR forecast Delhi's air quality to continue to be in the 'very poor' and 'poor' category for the next two days. She added that on Monday, local dust, transport, and biomass burning for warming needs, and emissions from Gautam Buddha Nagar and Faridabad districts were the primary drivers of pollution in the city.
