New Delhi, Jan. 4 -- Delhi's Air Quality Index deteriorated slightly early Sunday, January 4, while remaining in the 'poor' category. The AQI recorded around 8 am on Sunday was 298, as compared to 267 recorded around 4 pm on Saturday.

The System of Air Quality and Weather Forecasting and Research (SAFAR) forecast that Delhi's AQI is likely to reach near 390, approaching the 'severe' category, later in the day.

According to the Central Pollution Control Board (CPCB), an AQI between 0 and 50 is considered 'good', 51 to 100 'satisfactory', 101 to 200 'moderate', 201 to 300 'poor', 301 to 400 'very poor', and 401 to 500 'severe'.

The Air Quality Early Warning System predicted that the AQI is likely to remain in the 'very poor' category fro...