Record-breaking heatwaves, wildfires and human-caused emissions intensified ozone pollution, with Asia experiencing the highest exposure rates and major cities including Dhaka among the worst affected.
Around 34 percent of the world’s population was exposed to extremely high levels of ozone pollution during the first eight and a half months of 2026, as heatwaves and wildfires intensified air quality risks, according to a European Union report released on Wednesday.
The analysis by the EU’s Copernicus Climate Atmosphere Monitoring Service (CAMS), covering January 1 to September 15, highlighted the growing connection between climate change and air pollution.
Ground-level ozone forms when sunlight and heat react with emissions from wildfires, vehicles and industrial activities. Exposure can damage lung tissue, cause breathing difficulties, trigger asthma attacks and contribute to other health problems.
Although efforts to reduce the most harmful air pollutants have made progress in recent decades, ozone remains particularly difficult to control as climate change creates conditions that favour its formation.
Record-breaking heatwaves and wildfires across Europe and North America contributed to this year’s elevated ozone pollution, with smoke spreading far beyond the areas where the fires originated.
Indonesia has also experienced major wildfires. The El Nino weather pattern, which began in June and is expected to peak later this year, could fuel further fires in Southeast Asia, the analysis said.
“Air pollution does not stop at borders. It can travel thousands of kilometres, crossing continents and oceans and affecting air quality far from its source,” CAMS director Laurence Rouil said in the Atmosphere Watch report.
CAMS monitors air pollution and wildfires using satellite data and computer models.
The report classified 17 percent of the global population as exposed to “very poor” air quality, while only five percent experienced “good” ozone levels during the period covered.
The World Health Organization recommends a maximum ozone exposure level of 100 micrograms per cubic metre, averaged over eight hours.
Asia recorded the highest exposure to ozone pollution, with 53 percent of its population breathing air classified as “extremely poor” and another 22 percent experiencing “very poor” conditions.
Emissions associated with industrialisation, economic development and transport, alongside wildfires and the burning of agricultural residue, contributed to the continent’s widespread pollution.
New Delhi, Dhaka, Chongqing, a major Chinese metropolis, and Lahore in Pakistan were among the cities where ozone levels were classified as “extremely poor”.
In North America, two-thirds of the population faced “poor” or “very poor” air quality. The corresponding figure for Europe was 45 percent.
European Union regulations have helped reduce emissions of air pollutants, but ozone has remained an exception, the report said.
Ozone pollution is associated with 60,000 premature deaths annually in Europe, Ian Marnane, an official at the European Environment Agency, told a media briefing.
In North America, ozone levels also remained “relatively unchanged” despite ambitious policies aimed at reducing emissions, according to the report.
Across Africa, forest fire smoke, crop burning and cooking were identified as significant contributors to air pollution. Dust from the Sahara also travels as far as Europe.
Eight percent of Africa’s population experienced “extremely poor” air quality this year, while conditions were classified as “very poor” or “poor” for 19 percent.
In South America, ozone levels were very high in Sao Paulo and extremely elevated in Rio de Janeiro, both major Brazilian cities. Despite these local pollution hotspots, 81 percent of the continent’s population experienced “good” or “fair” air quality.
Oceania, including Australia and New Zealand, recorded the most favourable results among the regions highlighted. Around 66 percent of its population enjoyed “good” ozone levels, while the remaining 34 percent experienced “fair” conditions.
