Dhaka, Nov. 13 -- Dhaka ranked fourth among the world's most polluted cities on Friday morning, with an Air Quality Index (AQI) score of 160 at 9:30am.

The city's air quality was classified as 'unhealthy', indicating that pollution levels could pose health risks to the general population, according to the AQI scale.

India's Delhi topped the list with an AQI score of 334, followed by Manila in the Philippines with 171. Kolkata, also in India, ranked third with a score of 169.

According to the AQI scale, a reading of 101 to 150 is considered 'unhealthy for sensitive groups', while 151 to 200 is classified as 'unhealthy'. A reading between 201 and 300 is considered 'very unhealthy', while scores above 301 are classified as 'hazardous', po...