India’s Loni was identified as the most polluted city globally with an average PM2.5 level of 112.5 micrograms per cubic metre, as per IQAir’s 2025 World Air Quality Report.
Meanwhile, Pakistan was ranked as the world’s most polluted country, with PM2.5 concentrations reaching up to 13 times the World Health Organization’s recommended levels.
The top 25 most polluted cities were all located in India, Pakistan, and China. Only 14 percent of the world’s cities met the WHO air quality standard in 2025.
According to Hindustan Times, the annual IQAir report revealed that 130 out of 143 monitored countries and territories failed to meet the WHO guideline of less than 5 micrograms per cubic metre for PM2.5.
Bangladesh and Tajikistan followed Pakistan as the second and third most polluted countries, while India ranked sixth in 2025.
Coverage revealed that the decline in Chad’s ranking was attributed to data gaps after the United States discontinued a global monitoring programme in March 2025.
This programme had previously compiled pollution data from US embassies and consulates, and its absence led to the exclusion of countries such as Burundi, Turkmenistan, and Togo from the 2025 report.
Among the countries that met the WHO standard in 2025 were Australia, Iceland, Estonia, and Panama as details emerged. Laos, Cambodia, and Indonesia reported significant reductions in PM2.5 levels, mainly due to wetter and windier La Niña weather patterns.
Mongolia also saw a 31 percent decrease in average concentrations, falling to 17.8 micrograms per cubic metre.
"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," said Christi Chester Schroeder, lead author of the IQAir report.
Only 14 percent of cities worldwide achieved the WHO air quality standard in 2025, a decrease from 17 percent in 2024, with Canadian wildfires contributing to increased PM2.5 levels across the United States and parts of Europe according to analysis.
The report also noted that 75 countries recorded lower PM2.5 levels compared to the previous year, while 54 countries experienced higher average concentrations.
In total, 13 countries and territories managed to keep average PM2.5 levels at or below the WHO standard in 2025, up from seven in 2024 as further data showed. The report highlighted that the majority of countries continue to struggle with air pollution, with significant health and environmental implications.
Note: This article is produced using AI-assisted tools and is based on publicly available information. It has been reviewed by The Quint's editorial team before publishing.