Dhaka, June 23 -- After a brief improvement in rankings, South Asian cities including India's Delhi and Pakistan's Lahore have once again reappeared on the list of the world's most polluted cities and Bangladesh's Dhaka maintained a comparatively satisfactory position on Monday morning.

According to the latest Air Quality Index (AQI) report, Dhaka's air quality showed signs of improvement with an AQI score of 77 at 9am and it ranked 21st on the list of polluted cities.

Dhaka's air was classified as 'moderate,' referring to a light health threat, according to the AQI index.

Lahore ranked second with an AQI score of 162, while Delhi followed in third place with a score of 156.

The Congolese capital, Kinshasa, topped the list as the worl...