Delhi's air quality improves to 'very poor' from 'severe'; AQI at 398
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 between 401 and 500 is considered 'severe'.
Source: freepressjournal.in