India, Nov. 12 -- LUCKNOW A toxic canopy of smog and metallic fumes engulfed Lucknow on Diwali night, sending particulate pollution surging beyond national safety limits and reversing years of environmental gains, according to a report released by the CSIR-Indian Institute of Toxicology Research (CSIR-IITR) on Wednesday.

A 10-year comparative analysis from 2017 to 2026 showed that this year's air pollution was at concerning levels. Diwali night pollution peaked in 2018 when PM10 touched 990 micrograms per cubic meter, followed by a decline that bottomed out at 396 micrograms per cubic meter in 2022. However, the years after 2022 have reversed those gains. Compared with Diwali 2025, mean PM10 and PM2.5 concentrations in 2026 increased by ...