Dhaka, April 17 -- Dhaka ranked 5th among the world's most polluted cities on Friday morning, with an Air Quality Index (AQI) of 171 recorded at 9:10am.

The air quality was categorised as 'unhealthy', indicating a significant risk to public health, according to AQI standards.

Egypt's Cairo topped the list with an AQI of 658, followed by India's Delhi (328), Thailand's Chiang Mai (205), and Nepal's Kathmandu (181).

An AQI reading between 101 and 150 is considered 'unhealthy for sensitive groups', while 151-200 is classified as 'unhealthy'. Levels of 201-300 are deemed 'very unhealthy', and readings above 301 are labelled 'hazardous', posing severe health risks.

The AQI, which tracks daily air quality, indicates how polluted the air is ...