Dhaka, April 22 -- Dhaka, the densely populated capital of Bangladesh, ranked 7th among the world's most polluted cities on Wednesday morning, with an Air Quality Index (AQI) of 109 at 08:53 am.

The air was classified as 'Unhealthy for sensitive groups', means air quality is poor enough to cause health effects in vulnerable people, such as breathing discomfort, but the general public is unlikely to be affected, according to the AQI scale.

India's Delhi, Pakistan's Lahore and Nepal's Kathmandu were the three most polluted cities, with AQI scores of 273, 208 and 190.

An AQI between 101 and 150 is considered 'unhealthy for sensitive groups', while 151-200 is 'unhealthy', 201-300 is 'very unhealthy', and anything above 301 is 'hazardous' a...