Delhi, the capital of India, topped the list of the most polluted cities among 126 cities worldwide on Wednesday, with an air quality index (AQI) score of 277, which is classified as "very unhealthy." Following Delhi, Dhaka, the capital of Bangladesh, ranked second with a score of 258, also categorized as "very unhealthy." Kolkata, India, secured the third position with a score of 255, which is likewise considered "very unhealthy."

According to IQAir, a Switzerland-based organization, this live air quality index provides real-time information about the air purity of cities and offers warnings. Lahore, Pakistan, ranked fourth with an AQI score of 253, while Mumbai, India, came in sixth with a score of 242, both considered "very unhealthy" as well.

According to IQAir’s scale, a score between 51 and 100 is regarded as "moderate" or "acceptable," while scores between 101 and 150 are deemed "unhealthy for sensitive groups." A score between 151 and 200 indicates "unhealthy" air, and a score of 201 to 300 is categorized as "very unhealthy." Scores above 301 are considered "hazardous."

To mitigate the effects of air pollution in Dhaka, IQAir has recommended that sensitive groups wear masks when outdoors and avoid exercising outside.