New index to help prioritise pollution action in Delhi soon

The index by DPCC calculates which sources of pollution are responsible for PM2.5 safe standard of 60µg/m³ being breached

The Delhi Pollution Control Committee (DPCC) is planning to use a Priority Index, devised by IIT Kanpur, to tackle sources of pollution that contribute the most to Delhi’s pollution, officials said Friday. The index, formulated using data from the ongoing real-time source apportionment study, calculates which sources of pollution are responsible for the breaching of PM2.5 safe standards (60µg/m³). Sources with the highest contribution are tagged as severe or high priority sources and those with low contribution are classified as low priority sources, with the DPCC planning to take targeted action on the ground against sources in the high priority or severe category, the officials added.

Experts said both long-term and short-term strategies are needed to tackle these sources. (HT Photo)

The real-time source apportionment study, formally launched by Delhi chief minister Arvind Kejriwal in January this year, can identify and reveal the contribution of different sources of pollution at any given time of the day. Particulate Matter or PM2.5 is fine, inhalable particulate matter with a diameter of 2.5 microns. The pollutants can enter the bloodstream via the respiratory system and cause asthma, lung cancer, and heart disease.

The Priority Index (PI), devised last month, uses data gathered by IIT Kanpur since November last year— when the real-time source apportionment lab was made operational at Rouse Avenue — assigning priority values in 15-day periods to each of the 10 sources of pollution monitored. PI has four categories—severe or very high priority, high priority, moderate priority and low priority—to classify the 10 sources of pollution, which are secondary inorganic aerosols, soil and road dust, industries, pollution from the construction sector, vehicles, biomass burning, coal and fly ash, waste and plastic burning, residential or domestic pollution and “other” sources. Officials said this will allow the government to prioritise its resources to tackle the sources that require the most attention at that time.

For instance, from November 1 to 15, biomass burning, secondary inorganic aerosols and vehicles had the highest PI values, and were categorised in the severe or very high PI category. According to PI, three sources—vehicles, biomass burning and secondary inorganic aerosols—remained in the very high to high priority category from November until February, indicating they are constant sources of pollution in winter.

From May 1-15, the high priority sources have been being coal and fly ash, vehicles and “other” sources.

“PM2.5 levels in summer are much lower . Even then, sources with the highest index value require targeted action on the ground,” said a DPCC official.

Experts, meanwhile, said both long-term and short-term strategies are needed to tackle these sources. “We know vehicles are a constant source of pollution, both in summer and winter, so only long-term strategies will work,” Anumita Roychowdhury, executive director, research and advocacy at the Centre for Science and Environment, who was also part of the round-table conference, said.