New Delhi, Dec 11 : Residents of Delhi-NCR woke up to a cold Saturday morning as the minimum temperature dropped to 9 degrees Celsius, according to the India Meteorological Department (IMD). From Sunday onwards, the minimum temperature for the entire week will fluctuate between 7 to 8 degrees, while the maximum will remain 23 or 24 degrees, the IMD said. Meanwhile, Saturday's maximum temperature has been pegged at 24 degrees. The relative humidity at 8.30 a.m. was recorded at 87 per cent. After it had marginally improved two days ago, the national capital's Air Quality Index (AQI) has again fallen to the 'very poor' category. This morning at 9 a.m. the city's AQI stood at 301, as per System of Air Quality and Weather Forecasting And Research's (SAFAR) estimates. 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 level of PM 2.5 and PM 10 pollutants at 9 a.m. was recorded in the 'very poor' and 'poor' categories, respectively. The air quality is likely to be under the 'poor' category from December 12 to 13 and deteriorate to 'very poor' on December 14 and 15. /IANS