Dhaka among cities with poor ozone air
Dhaka was among major cities where ozone pollution reached “extremely poor” levels this year, alongside New Delhi, China’s Chongqing and Pakistan’s Lahore, as heatwaves, wildfires and human-caused emissions combined to expose a significant share of the world’s population to elevated ozone concentrations.
The findings were released on Wednesday by the European Union’s Copernicus Atmosphere Monitoring Service (CAMS) in an analysis covering the first eight months of 2026, highlighting the growing links between climate change and air pollution.
According to the report, 34 per cent of the global population was exposed to “extremely poor” ozone air quality between January 1 and September 15, with concentrations well above the World Health Organisation’s recommended exposure level.
The WHO guideline sets 100 micrograms of ozone per cubic metre as the maximum recommended exposure, averaged over eight hours.
Another 17 per cent of the world’s population experienced “very poor” ozone conditions, while only five per cent was exposed to “good” levels.
Asia recorded the highest proportion of people exposed to extremely poor ozone pollution, with 53 per cent of its population affected. A further 22 per cent experienced very poor ozone conditions.
The report attributed the continent’s high exposure to widespread emissions associated with industrialisation, economic development and transport, along with wildfires and the burning of agricultural residue.
Ground-level ozone forms when heat and sunlight react with pollutants released by wildfires, vehicles and industrial activities. Unlike ozone in the upper atmosphere, which protects the Earth from ultraviolet radiation, ground-level ozone can damage lung tissue, cause breathing difficulties, trigger asthma attacks and contribute to other health problems.
“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.
The analysis said record-breaking heatwaves and wildfires in Europe and North America contributed significantly to ozone pollution this year, with smoke travelling far beyond the areas where fires occurred.
Indonesia has also experienced major wildfires, while the warming El Niño weather pattern, which began in June and is expected to peak later this year, could contribute to further fires in Southeast Asia, according to CAMS.
Despite progress in reducing some of the most harmful air pollutants over recent decades, ozone has proved more difficult to control because climate change is strengthening the conditions that favour its formation.
In North America, about two-thirds of the population was exposed to poor or very poor air quality, while 45 per cent of Europe’s population faced similar conditions.
The report noted that EU regulations have helped reduce emissions of several air pollutants, but ozone remains an exception.
Ozone pollution is associated with around 60,000 premature deaths each year 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 emissions-reduction policies.
CAMS uses satellite observations and computer models to monitor atmospheric pollution and wildfire activity.
Africa also faced significant pollution from forest fires, crop burning and household cooking, while Saharan dust can travel as far as Europe. Eight per cent of the continent’s population experienced extremely poor ozone air quality this year, while 19 per cent faced poor or very poor conditions.
In South America, ozone levels were very high in São Paulo and extremely elevated in Rio de Janeiro, although 81 per cent of the continent’s population experienced good or fair air quality.
Oceania recorded comparatively better conditions, with 66 per cent of the population, including in Australia and New Zealand, experiencing good ozone levels and the remaining 34 per cent living under fair conditions.
The findings underscore the difficulty of tackling ozone pollution through emissions controls alone as rising temperatures, wildfires and changing weather patterns increasingly contribute to the formation and spread of ground-level ozone.
