IQAir, a Swiss air monitoring company that posts real-time air quality data aggregated from sensors around the world, has issued its annual report for 2025. The report shows that most of the world’s cities suffered from unhealthy levels of air pollution. Climate-driven wildfires and dust storms as well as the continuing burning of fossil fuels are driving toxic air across borders and worsening the problem.
Powerful wildfires in Canada and South Korea and dust storms in China, Texas, and other places made it harder for millions of people to breathe. As larger and more powerful storms occur more often, living far from the sources of pollution provides little protection.
Only 14% of the more than 9,000 cities included in the IQAir report met the World Health Organization’s target level for toxic particulate matter pollution. Global disparities in access to pollution data are a persistent problem, especially in Africa, Latin America, and West Asia.
A particularly serious problem is fine particulate matter – or PM2.5 – which is a mix of tiny particles of soot, smoke, and other substances that cause widespread health problems. In addition, WHO estimates that 4.2 million deaths annually worldwide are caused by fossil-fuel driven ambient air pollution.
Canadian wildfires drove much of the pollution increase. El Paso Texas was the most polluted major city in the US, driven largely by dust storms.
Air pollution doesn’t respect borders and is a problem most of the world faces.
