Overview
- IQAir’s World Air Quality Report, released Tuesday, ranks Pakistan the most polluted country and lists Loni in India as the worst‑polluted city with an annual PM2.5 average of 112.5 µg/m³.
- Only 13 of 143 countries met the WHO’s annual PM2.5 guideline of 5 µg/m³, while 130 fell short, and just 14% of cities met the standard, down from 17% in 2024; PM2.5 are fine particles that reach deep into the lungs and bloodstream.
- All of the 25 most polluted cities were in India, Pakistan, or China, with Bangladesh and Tajikistan ranking second and third most polluted countries and India placed sixth overall.
- The loss of US embassy and consulate monitors in March 2025 erased a key data source, which IQAir says likely skewed Chad’s apparent improvement and led to exclusions such as Burundi, Turkmenistan, and Togo.
- Large fires and weather shaped 2025 outcomes, with Canadian wildfire smoke lifting PM2.5 across North America and into parts of Europe, while wetter La Niña conditions drove notable declines in Laos, Cambodia, Indonesia, and a 31% drop in Mongolia.