Dhaka, March 8 -- Dhaka, the densely populated capital of Bangladesh, ranked third on the list of cities with the worst air quality, with an AQI score of 163 at 9:05am on Friday. Its air was classified as "unhealthy", referring to a health threat to residents, according to the AQI.When the AQI value for particle pollution is between 50 and 100, air quality is considered moderate, between 101 and 150, air quality is considered unhealthy for sensitive groups, between 150 and 200 is unhealthy, between 201 and 300 is said to be very unhealthy, and a reading of 301+ is considered hazardous, posing serious health risks to residents.Pakistan's Lahore, India's Delhi and Mumbai cities respectively occupied the first, second, and fourth spots on th...