Delhi continues to witness heightened levels of air pollution on Thursday as the overall air quality index (AQI) crosses 500-mark. This puts air quality in Delhi in the 'severe' category, according to System of Air Quality and Weather Forecasting And Research (SAFAR). Chandni Chowk in central Delhi witnessed an AQI of 532 on Thursday morning followed by Mathura Road and IIT-Delhi, both with an AQI of 500, ITO with an AQI of 474, Lodhi Road an AQI of 473, Delhi University an AQI of 472 and Pusa an AQI of 463 along with Dhirpur where SAFAR recorded an AQI of 459. Indira Gandhi International (IGI) Airport Terminal-3 recorded an AQI of 538. While pollutant particle PM2.5 continues to be the prominent pollutant across the national capital region (NCR), the concentration of PM10 was higher in Delhi's Ayanagar area with an AQI of 447. Delhi's neighbours in the NCR also witnessed high levels of air pollution with Noida in Uttar Pradesh recording an AQI of 514 on the morning of November 14 and Gurugram in Haryana an AQI of 554. The government and private schools in the Delhi and Noida will remain closed on Thursday and Friday.