Risk of Ozone Pollution

July 4, 2026

A comprehensive six-year data analysis (2021-2026) has revealed that ground-level ozone (O3) has expanded beyond isolated, short-lived spikes to become a widespread, yearround urban and regional problem in different regions of the country — and Delhi-NCR is emerging as the largest regional hotspot. Driven by intense and rising heat, bright sunlight and rising emissions of gases that form ozone, this invisible secondary pollutant is transforming the country’s air quality profile and associated risks. Rising ground-level ozone and prolonged exposure windows are transforming India’s localised, winter-time particulate problem into a year-round, transboundary crisis that peaks during the summer across all regions. Ozone is damaging public health, agricultural productivity and regional climate systems. While the current national clean air programme (NCAP) focuses particulate matter reduction, NCAP 2.0 must adopt a multi-pollutant strategy. By targeting precursor gases like NOx and VOCs that form ozone in the air, the new framework can accelerate the shift toward clean combustion, zero-emission pathways and integrated regional airshed management. Of 25 major Indian cities analysed between March 1 and May 10, 2026, 15 recorded summertime averages well above the National Ambient Air Quality Standard (NAAQS) of 100 microgramme per cubic metre (μg/m3) for a maximum eight-hour exposure. Chandigarh recorded the highest average summer ozone concentration among all cities. Jaipur recorded the second-highest ozone concentration. Delhi-NCR recorded the most persistent summer ozone pollution, with 71 and 62 exceedance days, respectively, followed by Bhopal (60), Bengaluru (55), Patna (24) and Muzaffarpur (21). Ahmedabad recorded the third-highest average summer ozone concentration. The problem has expanded far beyond traditional pollution zones, heavily concentrating in northern and western India. Chandigarh registered the highest summer-time average at a striking 173 μg/ m3, followed by Jaipur (120), Ahmedabad (115) and Bhopal (109). Mumbai exhibited a near year-round ozone footprint, with recurring exceedance clusters from January to April and again during November-December, indicating that ozone is no longer only a summer problem. Chennai recorded the highest episodic ozone concentration among all cities. Bengaluru is increasing spatial spread and prolonged ozone exposure.

(Courtesy: DTE)