India is the sixth most-polluted country when it comes to levels of fine particulate matter, a major air pollutant, as per the 2025 World Air Quality Report by IQAIR, a Swiss air quality technology company. With an annual average PM2.5 concentration of 112.5 µg/m³, Loni in Ghaziabad, Uttar Pradesh, was the most polluted city in the world.India’s New Delhi also ranked as the most polluted capital city worldwide, with an average PM2.5 concentration of 82.2 µg/m³.