Patna Apr 5 (IANS): Several cities in Bihar have witnessed an increase in air pollution levels, with Bhagalpur becoming the fifth most polluted city in the country.
On Tuesday, Bhagalpur registered an Air Quality Index (AQI) of 222, followed by Katihar (221), Bettiah (219), Begusarai (218), Saharsa (216), Muzaffarpur (181) and Patna (176).
An AQI between zero and 50 is considered "good"; 51 and 100 "satisfactory"; 101 and 200 "moderate"; 201 and 300 "poor"; 301 and 400 "very poor"; and 401 and 500 "severe".
However, the situation improved on Wednesday morning as the AQI in majority of the cities fell below the 200 mark.
Experts believe that the dust and toxic gases generated through vehicles and a large number of constructions of roads and buildings are responsible for the air pollution.