New Delhi, Oct. 25 -- Delhi's air quality remained in the 'very poor' category on Sunday with Air Quality Index (AQI) for the last 24 hours recorded at 349, Central Pollution Control Board (CPCB) said in its daily bulletin.

According to the bulletin, the National Capital Region (NCR) too witnessed the 'very poor' air quality with Ghaziabad's AQI recorded at 379, Noida's at 362, Greater Noida's at 392, Gurugram's at 317 and Faridabad's at 350.

An AQI between 0 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'.

The CPCB data showed all the values in Delhi-NCR in the 'red' category, which can cause respiratory illness on prolonged exposure....