Delhi's air quality improved to the 'very poor' category on Saturday, with the 24-hour average Air Quality Index (AQI) recorded at 370, officials said. The national capital's AQI stood at 429 in the 'severe' category on Friday, they said. 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'. The maximum temperature in Delhi was recorded at 23.4 degree Celsius, a notch above the season's average, while the minimum temperature settled at 7.6 degrees Celsius, one notch below the season's average, the India Meteorological Department (IMD) said. The city experienced fog in the morning hours, with humidity levels oscillating between100 per cent and 64 per cent, the department said. The weather office has predicted moderate fog on Sunday with the maximum and minimum temperatures expected to hover around 24 and eight degrees Celsius, respectively.