UP’s Loni world’s most polluted city, says report

• Loni in Uttar Pradesh is the most polluted city across the globe and Delhi is at the fourth spot, according to the World Air Quality Report 2025. 

• India is the sixth most-polluted country when it comes to levels of fine particulate matter (PM2.5). 

• The eighth edition of the report published by IQAir, a Swiss air quality technology company, analysed data from monitoring stations across 9,446 cities in 143 countries, regions and territories.

Key findings from the 2025 World Air Quality Report:

• Pakistan is the most polluted country, followed by Bangladesh, Tajikistan, Chad and Congo, with India at the sixth spot. 

• Among the ten most polluted cities across the globe, five are from India — Loni, Byrnihat, Delhi, Ghaziabad and Ula.

• The world's 25 most polluted cities were all located in India, Pakistan and China, with India home to three of the four most polluted. 

• Loni was the most polluted city, recording an annual average PM2.5 concentration of 112.5 g/m-a nearly 23 per cent increase from 2024 and more than 22 times the WHO guideline. 

• Comparing this year’s report to the previous year, 54 countries experienced a rise in the annual average of PM2.5, 75 saw a drop, two remained unchanged and 12 were newly represented in this year's dataset. 

• Only 14 per cent of global cities met the World Health Organisation (WHO) annual PM2.5 guideline of 5 g/m, down from 17 per cent the previous year. 

• Only 13 countries/territories met the WHO annual average PM2.5 guideline-French Polynesia, Puerto Rico, US Virgin Islands, Barbados, New Caledonia, Iceland, Bermuda, Reunion, Andorra, Australia, Grenada, Panama, Estonia. 

• Wildfires, intensified by climate change, played a major role in degrading global air quality in 2025. 

• Record biomass emissions from Europe and Canada contributed to approximately 1,380 megatons of carbon. 

• Canada was the most polluted country in Northern America for just the second time in the report's history, as its second-worst wildfire season on record affected air quality across Canada, the US and parts of Europe.

• In the United States, annual average PM2.5 levels increased to 7.3 g/m. 

• El Paso was the most polluted major city in the United States. 

• Seattle remained the cleanest major US city for the second consecutive year, with an annual average of 4.5 g/m. 

• Across Europe, 23 countries recorded a rise in annual average PM2.5 concentrations, 18 recorded a drop, and one was newly added.

• Switzerland and Greece experienced increases exceeding 30 per cent due to transboundary wildfire smoke from Northern America and Saharan dust from Africa. 

• Malta recorded the largest decrease at nearly 24 per cent.