It was observed that the air quality has further deteriorated in the last 201 hours. In an effort to prevent further degradation, the sub-committee decided that in addition to all works under Phase I and II, all works envisaged under Phase III of GRAP shall be implemented in the NCR with immediate effect, it said in an order Has gone. The pollution level in Delhi entered the ‘severe’ category after 4 November, when the AQI was . An AQI is considered ‘poor’ between and and ‘Very poor’ between 300 and ‘Severe’ between 401 and 401.