Delhi consistently ranks among the top 3 most polluted cities in the world . As of October 25, 2025, it is the most polluted city in the world , with air quality edging from unhealthy to very unhealthy, reporting levels above 186. Explore the top 10 most polluted cities in 2025, their air quality challenges, health and economic impacts, and the role of monitoring in improving clean air. New Delhi is the most polluted city in the world with an average AQI of 169, which is primarily caused by vehicular emissions, industrial activities, construction dust, and stubble burning in ... We analyzed data published by the World Air Quality Index project and put together the 2024 updated ranking of the “25 Cities with the Worst Air Pollution in the World ”.