Air Quality level downs to very poor category

Air Quality level downs to very  poor category

The air quality in Delhi on December 11 morning bordered "severe levels" and remained in the "very poor" category for the eighth consecutive day.
The air quality index (AQI) in the city was recorded at 399 at 8.41 am.
An AQI between 0-50 is considered "good", 51-100 "satisfactory", 101-200 "moderate", 201-300 "poor", 301-400 "very poor" and 401-500 "severe".
An AQI above 500 falls in the "severe plus" category.