Why Bad Air Needs To Be Fought On Several Fronts
Focusing on a single sector to improve air pollution in Delhi may not yield significant results. A study done by IIT-Kanpur in 2015 has shown that transport, biomass burning and industries are the biggest sources of pollution. A source apportionment study done by The Energy and Resources Institute (Teri) in 2018 has provided fresh data to work on the sources of pollution.
However, things are a bit complicated because Teri’s study highlights that only 36% of pollution in Delhi is its own doing, with 64% coming from NCR states and further north.
The IIT-Kanpur study identified biomass burning (17-26%) as the primary source of PM2.5 pollution in winter, followed closely by vehicles (20-25%). However, it also stated that secondary particles (25-30%) made up a significant chunk of PM2.5 in winter. “The winter sources include municipal solid waste burning (8-9%) and, to a lesser extent, soil and road dust. It is noteworthy that in winter the major sources for PM10 and PM2.5 are generally the same,” it added.
Teri’s study identified industries (30%), including thermal power plants, as the biggest source of PM2.5 pollution in winters, followed closely by vehicles (28%). Delhi’s own contribution was just 36% in winter and 34% was from NCR towns. The remaining 30% came from upwind regions outside the NCR, including transportation of dust from the Middle-East.
Council on Energy, Environment and Water (CEEW) in a March 2019 study titled “What is Polluting Delhi’s Air”, which included a 2010 CPCB study and a 2018 analysis by SAFAR, said there were variations in emission inventories for Delhi, primarily based on how sampling was done.
“The variations are due to several factors, including domain area, number of sampling stations, time period, season, quality of surveys, emission factors, assumptions, and data on emission abatement technologies and efficiency of control,” the CEEW analysis said.