Across Asia's great cities — from Dhaka to New Delhi, from Chongqing to Lahore — more than half the continent's people are breathing air that science classifies as extremely poor, a burden no other region on Earth carries so heavily. A new European Union atmospheric assessment reveals that ground-level ozone, born from the marriage of industrial emissions and rising heat, has reached concentrations far beyond what the human lung was made to endure. The crisis is not contained by borders: wildfire smoke from Europe and North America drifted across oceans this year, reminding us that the atmosph
Dhaka among Asian cities facing 'extremely poor' ozone pollution levels
Ozone exposure harms lungs and aggravates respiratory problems including asthma across 53% of Asia's population.
Air pollution does not stop at borders. It travels thousands of kilometres.
Mark
So Dhaka is in the worst category for ozone. What does that actually mean for someone living there?
Mimi
It means the air they're breathing is well above what the WHO says is safe. The ozone damages their lungs over time, and if they have asthma or other respiratory issues, it makes those worse every day.
Luke
But we should be clear—this is a measurement from January through mid-September. We don't know if it stays this bad year-round, or if it gets worse in winter.
Mark
What's causing it? Is it just Dhaka's own pollution?
Mimi
No, that's the thing. It's industrial growth, traffic, fires, agricultural burning—but also the climate itself. Heat makes ozone form more easily.
Luke
And the study says smoke from European and North American wildfires contributed this year. That's a real finding, but it's worth asking: how much of Asia's 53 percent is from local sources versus transboundary pollution? The study doesn't break that down.
Mark
So the warming climate is making this worse?
Mimi
Yes. Warmer temperatures create conditions that favor ozone formation and make it harder to control once it's there.
Luke
That's what the study says, but the mechanism there is worth understanding—it's not just that heat makes ozone; it's that the chemical reactions that create ozone happen faster and more readily in hot conditions.
Mark
What does "extremely poor" actually mean numerically?
Mimi
It's concentrations well above 100 microgrammes per cubic metre, the WHO threshold. The study doesn't give exact numbers for each city, though.
Luke
Right—we know Dhaka is in the category, but we don't know if it's 150 or 300. That's a gap in what we can say.
The Pulse
- Over 53% of Asia's population is now breathing ozone at 'extremely poor' levels — nearly 20 percentage points worse than the global average — making this the most severe regional air quality crisis on the planet.
- Ground-level ozone forms when traffic, industrial, and fire emissions cook under hot sun, and a warming climate is accelerating that chemistry, making the pollutant both more abundant and harder to suppress.
- Dhaka, New Delhi, Chongqing, and Lahore have emerged as among the worst-affected cities globally, where hundreds of millions face daily lung damage and worsening respiratory conditions including asthma.
- Wildfire smoke from Europe and North America crossed continents this year to degrade Asian air quality, exposing the borderless nature of a crisis that no single nation can solve alone.
- CAMS satellite monitoring is giving the world an unprecedented picture of the scale, but the data raises an urgent question: can emission sources be cut fast enough to reverse the trend before warming pushes the numbers higher still?
Across Asia's great cities — from Dhaka to New Delhi, from Chongqing to Lahore — more than half the continent's people are breathing air that science classifies as extremely poor, a burden no other region on Earth carries so heavily. A new European Union atmospheric assessment reveals that ground-level ozone, born from the marriage of industrial emissions and rising heat, has reached concentrations far beyond what the human lung was made to endure. The crisis is not contained by borders: wildfire smoke from Europe and North America drifted across oceans this year, reminding us that the atmosphere is a single shared commons, and what we release into it anywhere eventually arrives everywhere.
Dhaka is breathing some of the worst air on Earth — and so are New Delhi, Chongqing, and Lahore. A new assessment by the European Union's Copernicus Atmosphere Monitoring Service has classified these Asian cities as reaching "extremely poor" ozone pollution levels, concentrations far exceeding the World Health Organization's safety threshold of 100 microgrammes per cubic metre over eight hours.
The scale across the continent is staggering. Some 53 percent of Asia's population is exposed to ozone at these extreme levels — the highest proportion of any region on the planet — while another 22 percent experience "very poor" conditions. Globally, 34 percent of the world's population faced extremely poor ozone exposure in the first nine months of this year. Asia's burden is nearly 20 percentage points worse than that average. Only five percent of humanity breathed air classified as good.
Ground-level ozone forms when pollutants from traffic, industry, and fires react chemically under hot, sunny conditions. The health consequences are direct: lung damage and worsened respiratory ailments, particularly asthma, for hundreds of millions of people for whom this is not an abstract statistic but a daily physiological reality.
The drivers are multiple and reinforcing. Industrial expansion, denser transport networks, wildfires, and agricultural burning all feed ozone formation. But the deeper accelerant is the warming climate itself — rising temperatures create precisely the atmospheric conditions that favor ozone production and make it harder to control once formed.
The problem does not respect borders. Wildfire smoke from Europe and North America traveled thousands of kilometres this year, degrading air quality across Asia. CAMS director Laurence Rouil has emphasized that air pollution moves with wind and weather, indifferent to political boundaries. What burns in one hemisphere reaches the lungs of people in another — and the question now is whether the world can reduce ozone's sources fast enough to reverse the trend before warming and industrial growth push the numbers higher still.
Dhaka is breathing some of the worst air on Earth. So are New Delhi, Chongqing, and Lahore. According to a new assessment by the European Union's Copernicus Atmosphere Monitoring Service, these Asian cities have reached what the monitoring agency classifies as "extremely poor" ozone pollution levels—a category that represents concentrations far exceeding the World Health Organization's safety threshold of 100 microgrammes per cubic metre, measured over eight hours.
The scale of the problem across Asia is staggering. More than half of Asia's population—53 percent—is now exposed to ozone at these extremely poor levels, the highest proportion of any region on the planet. Another 22 percent of Asians experience what CAMS calls "very poor" conditions. By comparison, globally, 34 percent of the world's population faced extremely poor ozone exposure between January 1 and September 15 of this year, with 17 percent in the very poor category. Only five percent of humanity breathed air classified as good. The disparity is sharp: Asia's burden is nearly 20 percentage points worse than the global average.
Ozone at ground level forms when pollutants from traffic, industry, and fires chemically react under hot, sunny conditions. The health consequences are direct and serious. Exposure damages the lungs and worsens respiratory ailments, particularly asthma. For the hundreds of millions of people across Asia living in extremely poor ozone zones, this is not an abstract environmental statistic—it is a daily physiological burden.
The sources driving Asia's ozone crisis are multiple and interconnected. Industrial and economic expansion has accelerated emissions across the region. Transportation networks have grown denser and more congested. Wildfires and the burning of agricultural residue release pollutants that feed ozone formation. But there is a deeper driver: the warming climate itself. Rising temperatures create the exact atmospheric conditions that favor ozone production, and they make the pollutant harder to control once formed. Heat amplifies chemistry.
The problem does not stay put. Smoke from major wildfires in Europe and North America this year traveled thousands of kilometres, crossing continents and oceans, and degraded air quality far from where the fires burned. Laurence Rouil, director of CAMS, underscored the borderless nature of air pollution: it moves with wind and weather, indifferent to political boundaries. What burns in one hemisphere affects the lungs of people in another.
CAMS tracks this pollution using satellite data and computer models, giving the world a detailed picture of where and how badly ozone concentrations have climbed. The data shows that Asia's crisis is not a localized problem in a handful of cities—it is a continental one, touching the majority of the region's population. The question now is whether the sources of ozone pollution can be reduced fast enough to reverse the trend, or whether warming and continued industrial growth will push the numbers higher still.
Notable Quotes
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.— Laurence Rouil, Director of Copernicus Atmosphere Monitoring Service
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