Dhaka's air ranked as 7th most polluted among cities around the world this morning, according to Air Quality Index (AQI).

The air in Dhaka city was categorised as "unhealthy" with an AQI score of 159 at 9am.

This comes despite most Dhaka roads wearing an almost deserted look on the Eid holiday. Only a few private cars, auto-rickshaws, and rickshaws were found moving on city roads this morning.

Delhi, Kathmandu, and Kolkata occupied the first three spots on the list, with AQI scores of 275, 199, and 194 respectively.

Yesterday, Dhaka ranked fourth in air pollution with an AQI of 182.

Swiss-based organization IQAir regularly monitors air pollution levels. Their real-time index informs people about how clean or polluted the air is in a specific city and raises awareness.

When the AQI value for particle pollution is 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", while a reading of 301+ 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.