Delhi's air quality has deteriorated further as it slipped from the 'moderate' category to 'very poor', with the city recording an overall Air Quality Index (AQI) at 312, according to the System of Air Quality and Weather Forecasting And Research (SAFAR).
The air quality in the national capital was in the 'satisfactory' category continuously for three days from January 9 to January 11, while it slipped to the 'moderate' category on January 12.
Meanwhile, the air quality in Noida and Gurugram is in the 'poor' category. The AQI in Noida stands at 262, while Gurugram's AQI is at 256.
As per the government agencies, 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 401 and 500 'severe'.