Smaller and upcoming cities emerging as pollution hotspots, says report.
The levels of PM 2.5, the most threatening of particulate matter, worsened in 43 out of 99 cities whose winter air in two years, 2020 and 2019, was compared by the Centre for Science and Environment (CSE).
Only 19 registered “substantial improvement” — and one of these was Chennai. The restof the cities did not experience significant change.