India’s battle against air pollution is entering a new phase as ground level ozone pollution increasingly threatens public health during summer months. Traditionally, winter has been considered the most dangerous season for air quality due to the accumulation of particulate matter caused by stagnant weather conditions. However, experts now warn that the seasonal relief usually experienced during summer is fading as rising temperatures and intense sunlight fuel the formation of ozone pollution across major cities.
According to the latest State of Global Air 2025 report, India ranks third globally in exposure to ozone pollution. The report estimates that long term exposure to ground level ozone contributed to around 470,000 deaths worldwide in 2023, with nearly half of those deaths occurring in India. Scientists say the country’s combination of strong sunlight, increasing temperatures and high emissions from vehicles, industries, diesel generators and waste burning creates ideal conditions for ozone formation.
Rising Temperatures and Urban Emissions Fuel Ozone Build Up
Unlike particulate matter, ground level ozone is not emitted directly into the atmosphere. Instead it forms when pollutants such as nitrogen oxides, carbon monoxide and volatile organic compounds react in the presence of heat and ultraviolet sunlight. As temperatures rise, these chemical reactions become more intense, resulting in higher ozone concentrations.
An analysis conducted by the Centre for Science and Environment (CSE) using data from 25 major Indian cities between 2021 and May 2026 shows that ozone pollution is becoming a widespread urban problem. Data collected between March and May this year revealed that 15 cities recorded seasonal average ozone concentrations exceeding 100 micrograms per cubic metre, the limit prescribed under India’s National Ambient Air Quality Standards for eight-hour exposure.
Experts say climate change is worsening the situation. Higher temperatures not only speed up ozone formation but also increase the release of volatile organic compounds from vegetation and human activities. This combination is making summer air quality increasingly hazardous despite lower levels of visible particulate pollution.
Doctors Report Unexpected Respiratory Problems During Summer
Medical professionals are also noticing unusual patterns in respiratory illnesses during the hottest months of the year. Ground level ozone is known to irritate airways, trigger inflammation and reduce lung function. Even short term exposure can cause coughing, throat irritation, wheezing, chest tightness and breathing difficulties.
Doctors who normally reduce asthma medication doses during summer are now reporting unexpected flare ups among patients. Specialists believe ozone may be acting as an under-recognised environmental trigger, especially when combined with dust, pollen and extreme heat.
Health experts point out that ozone is a powerful oxidant capable of increasing airway sensitivity and worsening allergic reactions. International studies have linked periods of elevated ozone pollution with increased asthma attacks, higher use of emergency medication and more hospital visits, particularly among children and individuals with pre-existing respiratory conditions.
Researchers are calling for detailed studies to better understand the relationship between ozone pollution and the growing number of respiratory problems being observed during India’s increasingly hot summers. As temperatures continue to rise, experts warn that tackling ozone pollution may become just as important as controlling particulate matter in the fight for cleaner air.