Delhi on Wednesday witnessed 'severe' air quality, with an air quality index (AQI) of 413 at around 7 am, according to data from Central Pollution Control Board (CPCB). Wazirpur recorded an AQI of 458, while areas around India Gate and Kartavya Path registered an AQI of 408. Authorities on Tuesday imposed Graded Response Action Plan (GRAP) Stage 3 anti-pollution measures.