In the real-time air quality ranking, Dhaka scored 170 on Tuesday, according to AirVisual. Also Read- Dhaka air pollution today world's worstBangladesh, one of the most densely-populated countries in the world, has been struggling with air pollution for a long time. Also Read- Sound pollution: Beyond permissible levels in all divisionsThe United States Environmental Protection Agency developed the Air Quality Index (AQI) to measure air quality. An AQI value over 300 represents hazardous air quality, and below 50 the air quality is good. The AQI debuted in 1968, when the National Air Pollution Control Administration undertook an initiative to develop an air quality index, and to apply the methodology to Metropolitan Statistical Areas.

Source: Dhaka Tribune February 20, 2019 05:15 UTC