Pakistan has been ranked as the world’s most polluted country in 2025, with levels of fine particulate matter (PM2.5) reaching up to 13 times the limit recommended by the World Health Organization (WHO), according to a report released by Swiss air quality monitoring firm IQAir.
The report found that 130 out of 143 monitored countries and territories failed to meet the WHO guideline of less than 5 micrograms per cubic metre. Only 13 countries met the standard in 2025, up from seven a year earlier.
Bangladesh and Tajikistan ranked second and third among the most polluted countries. Chad, which topped the list in 2024, dropped to fourth place, although researchers said the decline may reflect gaps in data rather than actual improvement.
The report noted that the United States shut down a global air quality monitoring programme in March, removing a key data source for several countries. As a result, Burundi, Turkmenistan and Togo were excluded from the 2025 rankings.
At the city level, Loni in India recorded the highest pollution levels, followed by Hotan in China’s Xinjiang region. The 25 most polluted cities were all located in India, Pakistan and China.
Globally, only 14 percent of cities met WHO air quality standards, down from 17 percent in 2024. Wildfires in Canada contributed to higher pollution levels across parts of the United States and Europe.
The report said 75 countries recorded a decline in PM2.5 levels in 2025, while 54 saw an increase. Countries including Laos, Cambodia and Indonesia reported improvements, largely due to wetter and windier La Nina conditions, while Mongolia saw a significant reduction in pollution levels.
