Patna, Dec 13 (IANS): While the temperature is dipping across most of the country, the Air Quality Index (AQI) continues to remain above severe in most of the cities.

In the list of 10 cities with the most air pollution, six are in Bihar.

Saharsa is considered as the most air polluted city in the country having an air quality index of 366 which comes as health hazards for people having asthmatic problems.

Besides Saharsa, Muzaffarpur was at 344, Bhagalpur at 330, Patna at 318, Begusarai at 270 and Purnea at 269, as per data recorded at 8 p.m. on Monday.

An official, however, said that the AQI of Saharsa and Muzaffarpur crossed the 400 mark during the daytime.

The official said that the dust is the main reason for deterioration of AQI in these cities. Rampant construction, and transportations of sand and construction materials are the main reasons for AQI deterioration. As a result of this, PM 2.5 and PM 10 levels increased five and threefolds from the normal days.

AQI from 0 to 50 is considered as good, from 51 to 100 moderate, from 101 to 150 is considered "unhealthy for the sensitive group, from 151 to 200 is considered unhealthy for all, from 201 to 300 is very unhealthy, and from 301 to 500 are hazardous for human health.