SINGAPORE – Pakistan has been ranked the world’s most polluted country in 2025, with concentrations of fine particulate matter (PM2.5) reaching levels up to 13 times higher than the World Health Organization (WHO) guideline, according to a report released by Swiss air quality monitoring firm IQAir.
The annual report showed that only 13 countries and territories maintained average PM2.5 levels within the WHO standard of less than 5 micrograms per cubic metre, up from seven in 2024. Overall, 130 of the 143 monitored countries failed to meet the recommended limit. Bangladesh and Tajikistan ranked second and third in global pollution levels, while Chad, the most polluted country in 2024, fell to fourth, though data gaps due to monitoring interruptions may have influenced this change.
IQAir noted that the US closure of its global monitoring program last March, which collected pollution data from embassies and consulates, removed a key data source for many countries. This led to uncertainties in PM2.5 estimates for several regions, including Chad, Burundi, Turkmenistan, and Togo.
At the city level, India’s Loni was the most polluted, with an average PM2.5 concentration of 112.5 micrograms per cubic metre, followed by Hotan in China’s Xinjiang region at 109.6 micrograms. All of the world’s 25 most polluted cities were located in India, Pakistan, and China. Only 14% of cities globally met WHO air quality standards, down from 17% the previous year, with Canadian wildfires contributing to elevated PM2.5 levels across the United States and parts of Europe.
On a positive note, countries including Australia, Iceland, Estonia, and Panama met air quality standards, while Laos, Cambodia, Indonesia, and Mongolia recorded significant reductions in PM2.5 levels due to wetter and windier La Niña conditions. Overall, 75 countries reported lower average PM2.5 concentrations compared to 2024, while 54 saw increases.
The findings underscore the ongoing global challenge of air pollution and its impact on health, particularly in South and East Asia, where urban and industrial emissions remain a major concern.
