India has been ranked the sixth most polluted country in the world in terms of fine particulate matter (PM2.5), according to the World Air Quality Report 2025. The report also highlights that Uttar Pradesh's Loni is the most polluted city globally, while Delhi holds the fourth position.
India's position in global rankings
The eighth edition of the report, released by Swiss air quality technology company IQAir, analysed data from monitoring stations across 9,446 cities in 143 countries, regions and territories, reported The New Indian Express.
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Pakistan emerged as the most polluted country, followed by Bangladesh, Tajikistan, Chad and Congo, with India placed sixth. Among the world's 10 most polluted cities, five are in 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, India, was the most polluted city, recording an annual average PM2.5 concentration of 112.5 µg/m³-a nearly 23 per cent increase from 2024 and more than 22 times the WHO guideline," the report said.
Global trends in air quality
The report noted mixed trends across countries. While 54 countries recorded an increase in annual PM2.5 levels, 75 saw a decline, two remained unchanged and 12 were newly added to the dataset.
"Only 14 per cent of global cities met the World Health Organization (WHO) annual PM2.5 guideline of 5 µg/m³, down from 17 per cent the previous year. Only thirteen 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," the report said.
Role of climate and wildfires
Wildfires, intensified by climate change, played a major role in worsening air quality worldwide in 2025. Large-scale biomass emissions from Europe and Canada contributed to around 1,380 megatons of carbon.
Canada recorded its second-worst wildfire season, impacting air quality not only within the country but also across parts of the United States and Europe. In the US, PM2.5 levels rose to 7.3 µg/m³, with wildfire smoke and dust storms contributing to the increase.
The report also flagged concerns over reduced access to air quality data. The shutdown of the US State Department's monitoring programme in March 2025 affected data availability in several regions.
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Monitoring efforts in 44 countries were weakened, while six countries were left without any monitoring systems, according to the Centre for Research on Energy and Clean Air (CREA).
Experts stress need for action
"Air quality is a fragile asset that requires active stewardship to protect public health. The 2025 World Air Quality Report makes clear that without monitoring, we cannot fully understand what's in the air we breathe. Expanding access to real-time data empowers communities to act. By reducing emissions and addressing climate change, we can drive meaningful, lasting improvements in global air quality," IQAir Global CEO Frank Hammes was quoted as saying by TNIE.
"The World Air Quality Report reveals two competing realities: an air pollution crisis and the rise of communities, scientists and data working to meet the challenge. In 2025, familiar culprits like industrial agriculture, wildfires and fossil fuels left their mark in the data collated by IQAir worldwide," said Aidan Farrow, Senior Scientist, Greenpeace International.
"This open, transparent data is an essential tool for holding polluters accountable and securing a healthy environment for everyone," he said.
