Dhaka, March 23 -- Dhaka's air quality is in the 'unhealthy' zone this morning.

With an air quality index (AQI) score of 137 at 8:56 am, Dhaka ranked eighth in the list of cities worldwide with the worst air quality.

An AQI between 101 and 200 is considered 'unhealthy', particularly for sensitive groups.

Pakistan's Lahore, India's Delhi and Thailand's Chiang Mai occupied the first three spots in the list, with AQI scores of 186, 180 and 164, respectively.

An AQI between 201 and 300 is said to be 'poor', while a reading of 301 to 400 is considered 'hazardous', posing serious health risks to residents.

In Bangladesh, the AQI is based on five criteria pollutants -- Particulate Matter (PM10 and PM2.5), NO2, CO, SO2 and Ozone.

Dhaka has ...