The air quality across the national capital showed some improvement as Delhi recorded an overall Air Quality Index (AQI) of 307, in the ‘very poor’ category on Tuesday morning, according to the data recorded at 7:00 AM by the Central Pollution Control Board (CPCB).Delhi’s air quality deteriorated after Diwali celebrations held on Jattvibeday. The persistent pollution is compounded by a drop in temperatures and moderate fog.The Delhi government is taking pollution control measures to minimise the impact of the particulate matter by using water sprinklers across the State.Chandni Chowk recorded the capital’s highest Air Quality Index at 395, in the ‘very poor’ category, followed by Punjabi Bagh at 355 and Aya Nagar at 354, also in the same category. RK Puram recorded an AQI of 328, categorised as ‘very poor’. The AQI around the Safdarjung area was recorded at 371, in the same category.Anand Vihar and Ashok Vihar stood at an AQI of 290 and 278, respectively, in the ‘poor’ category.Narela recorded an AQI of 272 in the ‘poor’ category, followed by India Gate and Kartavya Path at 258 in the same category.According to the India Meteorological Department (IMD), Delhi registered a morning temperature of 17.0°C accompanied by moderate fog. The IMD has predicted moderate fog to remain persistent for the next 5 days.Meanwhile, the overall Air Quality Index in Ambala, Haryana, is recorded at 250, categorised as ‘Poor’, as per the CPCB.The overall AQI in Maharashtra was recorded at 146, categorised as ‘Moderate’.Earlier on Monday, a day after Diwali, the air quality deteriorated to the ‘severe’ category at several monitoring stations, with the Air Quality Index crossing 400 in multiple areas and visibility remaining poor during the early morning hours.According to CPCB classification, an AQI between 0 and 50 is considered ‘good’, 51-100 ‘satisfactory’, 101-200 ‘moderate’, 201-300 ‘poor’, 301-400 ‘very poor’ and 401-500 ‘severe’.