Pakistan ranked as the most polluted country in 2025 in a recent report. The country recorded particulate matter known as PM2.5 up to 13 times higher than recommended World Health Organisation levels, the report by Swiss IQAir showed on Tuesday.
The particles come from combustion, industrial processes, and dust and can cause health concerns.
The reports also showed that 130 out of 143 monitored countries and territories failed to meet the WHO standards.
Bangladesh and Tajikistan ranked the second and third in the list.
Among cities, India’s Loni was the world's most polluted city in 2025, with an average of PM2.5 levels of 11.5 micrograms, followed by Hotan in the northwestern Chinese region of Xinjiang at 109.6 micrograms
All of the world's most polluted cities were in India, Pakistan and China.
Only 14 per cent of the world's cities met the WHO standard in 2025, down from 17 per cent a year earlier, with Canadian wildfires driving up PM2.5 across the United States and as far as Europe.
Only 13 countries met the average PM2.5 levels of having less than 5 micrograms per cubic meter in 2025, up from seven in 2024.
The countries that met the standard were Australia, Iceland, Estonia and Panama.
About 75 countries reported lower PM2.5 levels in 2025 compared to a year earlier, while 54 recorded higher concentrations, IQ Air said.
The data this year has been considerably lower compared to 2024 as the United States shut down a global monitoring programme that compiled pollution data collected from its embassy and consulate buildings, citing budget constraints.
The lead author of the IQAir report, Christi Chester Schroeder, said, "The loss of the data in March made it appear there was a significant drop in PM2.5 levels (in Chad), but the fact of the matter is that we don't know."
The decision led to a loss of data in many smog-prone countries like Burundi, Turkmenistan and Togo.