Wazzup Pilipinas!?
For decades, the Indian narrative on air pollution has been dictated by a predictable winter rhythm. As temperatures drop, a thick shroud of smog descends upon northern cities, igniting urgent headlines about coal combustion, vehicular exhaust, and the seasonal scourge of stubble burning.
But this familiar script is being rewritten by an invisible, relentless adversary. Ground-level ozone (O3)—a potent, colourless pollutant—is rapidly emerging as a year-round threat, thriving not in the cold, but under the relentless intensity of summer sun and heat.
A Dangerous Chemical Cocktail
Unlike particulate matter (PM 2.5 and PM 10
), which can be traced back to a specific smokestack or tailpipe, ozone is not emitted directly by human activity. Instead, it is a secondary pollutant "baked" into existence in the open air.
When primary pollutants—nitrogen oxides (NOx
), carbon monoxide (CO), and volatile organic compounds (VOCs)—are released by urban metabolism, they mix in the lower atmosphere. Under intense ultraviolet sunlight and heat, they undergo photochemical reactions to form ozone.
As Pallavi Pant, head of global initiatives at the US-based Health Effect Institute, warns: "Warmer air causes ozone to form faster. So periods with higher temperature such as heatwaves can result in more ozone production, resulting in poorer air quality"
The Human Toll
The health implications are severe. Ozone is a highly reactive, toxic gas that causes acute, immediate damage to the respiratory system.
Immediate Impact: Exposure triggers severe inflammation, irritates airways, and can cause coughing, throat irritation, chest tightness, and wheezing.
Long-Term Damage: It shrinks lung capacity and causes damage to cell membranes lining the respiratory tract.
Existing Conditions: For millions living with asthma or chronic obstructive pulmonary disease (COPD), ozone exposure accelerates tissue degradation and worsens symptoms.
According to the "State of Global Air 2025" report, India ranks third globally in exposure to ozone pollution. In 2023, long-term exposure to ozone was linked to an estimated 470,000 deaths worldwide, roughly half of which occurred in India.
Beyond the Winter Script
A comprehensive analysis of data from 25 major Indian cities (2021–2026) by the Centre for Science and Environment (CSE) reveals that the problem is no longer confined to isolated, short-lived spikes.
Urban Reality: During the summer of 2026 (March 1–May 10), 15 of the 25 analysed cities recorded seasonal average concentrations exceeding the 100 μg/m3
safety limit set by the National Ambient Air Quality Standards.
Widespread Coverage: Chandigarh recorded the highest concentration at 173 μg/m3, followed by Jaipur (120 μg/m3), Delhi-NCR (118 μg/m3), Ahmedabad (115 μg/m3), and Bhopal (109 μg/m3).
After-Dark Exposure: Contrary to historical belief that ozone dissipates after sunset, urban residents are now facing ozone exposure well into the night, particularly during heatwaves.
A Regulatory Blind Spot
Tackling ozone requires moving beyond the current "dust-sweeping" approach of the National Clean Air Programme (NCAP). Because ozone is formed from complex chemical interactions, standard air pollution strategies can inadvertently backfire.
If a government aggressively cuts NOx
emissions without simultaneously addressing VOCs (from paints, solvents, and industrial chemicals), local ozone concentrations can paradoxically increase. This phenomenon is the ultimate regulatory blind spot.
The Path Forward
To manage this multi-domain crisis, India must shift from treating air pollution as a localised winter problem to managing it as a dynamic, transboundary climate-chemistry puzzle.
Learning from global examples—such as California’s success in breaking the chemical loop or China’s shift to integrating VOC controls—India needs an ozone-centred approach. This must include:
Unified Policy: Integrating air quality and climate policy to target both NOx and VOCs.
Airshed-Based Management: Moving beyond rigid city boundaries to deploy regional action plans across states.
Source Control: Accelerating the transition to zero-emission transport and enforcing strict industrial and evaporative standards.
As the summer sun continues to turn cities into atmospheric ovens, the message is clear: the time for a sophisticated, multi-pollutant strategy is now. Ignoring the invisible chemistry of our atmosphere is no longer an option.
Ross is known as the Pambansang Blogger ng Pilipinas - An Information and Communication Technology (ICT) Professional by profession and a Social Media Evangelist by heart.
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