Delhi's air quality, which had remained in the 'very poor' to 'severe' categories for several weeks, showed improvement on Thursday. The AQI stood at 221, classified as 'poor'. Some Delhi-NCR pockets, including Sri Aurobindo Marg, IGI Airport and Lodhi Road, among others even recorded 'moderate' air. Despite this improvement, a thin layer of smog persisted in parts of the city.