Dhaka again continues to ranks high among cities that have the lowest quality of air in the world.
By the US Air Quality Index (AQI), Bangladesh’s capital ranked as the fourth most polluted city, with a score of 176.
According to data available from AirVisual
, a smartphone application which shows the user real-time air pollution indices for any city across the globe, Dhaka’s score signifies unhealthy air quality.
India’s capital Delhi topped the index as the most polluted city, with a score of 182.
The United States Environmental Protection Agency (EPA) developed the Air Quality Index to report air quality. This AQI is divided into six categories, indicating increasing levels of health concern.
An AQI value over 300 represents hazardous air quality, and below 50, the air quality is good.
The index is based on the criteria of five pollutants regulated under the Clean Air Act– ground-level ozone, particulate matter, carbon monoxide, sulfur dioxide, and nitrogen dioxide.
The AQI debuted in 1968, when the US National Air Pollution Control Administration undertook an initiative to develop an air quality index and to apply the methodology to gauge Metropolitan Statistical Areas worldwide.