Delhi's air quality slips to 'severe' category again; dip in temperature pushes National Capital's AQI to 414

New Delhi: The air quality in Delhi worsened once again, slipping into the 'severe' category on Tuesday morning. At 9.36 am, the air quality index (AQI) was at 414. The AQI at Bawana, Wazirpur, Anand Vihar and Rohini was 445, 442, 442 and 440 respectively.According to the government air quality monitoring service SAFAR, the city's air quality was in 'very poor' category on Monday which turned to severe by the evening. The average AQI stood at 360 on Sunday.In the National Capital Region (NCR), the AQI in Noida was 436, while Ghaziabad recorded an AQI of 445. Greater Noida, Gurgaon and Faridabad recorded AQI of 436, 365 and 404 respectively.On Monday, most of the 37 air quality monitoring stations in Delhi recorded air quality in the 'severe' category.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'. Above 500 falls in the 'severe plus' category.With the winter setting in, a dip in the minimum temperature makes the air cold and heavy leading to accumulation of pollutants close to the ground.