The monitoring firm says fine particles in Pakistan’s air last year were among the highest in the world, 13 times higher than WHO guidelines.
Published on 24 March 2026
Pakistan was the world’s smogiest country in 2025, with concentrations of hazardous fine particles called PM2.5 13 times higher than World Health Organization (WHO) recommended levels, a report has found.
In its annual report published on Tuesday, Swiss air quality monitoring firm IQAir said only 13 countries and territories managed to keep their average fine particle levels below the WHO guideline, but that number was up from seven in 2024.
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IQAir obtained data from 9,446 cities in 143 countries, regions and territories. Overall, 130 out of 143 monitored countries and territories failed to meet the WHO standard.
This standard is based on the measurement of fine particles in the air with a diameter of 2.5 microns or less. The WHO standard for healthy air quality is average PM2.5 not exceeding 5 micrograms per cubic metre. Pakistan’s PM2.5 level was 67.3 micrograms.
Pakistan’s average PM2.5 concentration in 2024 was 73.7 micrograms.
PM2.5 is thought to be a major contributor to premature birth, while long-term exposure is also linked to a higher likelihood of neurodegenerative conditions including dementia, Parkinson’s disease and Alzheimer’s disease.
Bangladesh and Tajikistan ranked second and third in IQAir’s list of most polluted countries, while Chad, statistically the country with the most smoke in 2024, was ranked fourth in 2025.
However, there is a clear decline in PM2.5 levels possibly the result of gaps in the data.
The United States last year shut down a global monitoring program that compiled pollution readings from its embassy and consulate buildings, citing budget constraints.
The decision eliminated the primary data source for several smog-prone countries, and led to the exclusion of Burundi, Turkmenistan and Togo from the 2025 report due to information gaps.
“Since the loss of data in March, it appears that there has been a significant decline in PM2.5 levels (in Chad), but the truth of the matter is that we don’t know,” said Christie Chester Schroeder, lead author of the report.
India’s Loni is the most polluted city
Loni, a city in northern India, was identified as the world’s most polluted city in 2025 with an average PM2.5 level of 112.5 micrograms per cubic metre. Hotan in northwestern China’s Xinjiang region was in second place, with a level of 109.6 micrograms.
The report found that all of the world’s top 25 most polluted cities were in China, India and Pakistan.
Globally, only 14 percent of cities met the WHO air quality standard in 2025, down from 17 percent a year earlier. Australia, Iceland, Estonia and Panama were among the 13 countries that met WHO guidelines last year.
Laos, Cambodia and Indonesia recorded significant reductions in PM2.5 compared to 2024, mainly due to wet and windy weather due to the La Nina phenomenon. Mongolia’s average PM2.5 concentration fell 31 percent to 17.8 micrograms per cubic meter.
Overall, 75 countries recorded lower PM2.5 levels in 2025 than a year earlier, while 54 saw higher average concentrations, IQAir said.
Climate change-induced wildfires were a major factor behind global air quality worsening by 2025, as record levels of biomass burning in Europe and Canada emitted about 1,380 megatonnes of carbon.
