New Delhi, Dec 10 (IANS): Delhi's Air Quality Index (AQI) again inched closer to the 'very poor' category as it slipped to 293 at 9 a.m. Friday morning, System of Air Quality and Weather Forecasting And Research's (SAFAR) data said.

The level of PM 2.5 and PM 10 pollutants in the air were recorded at 'poor' and 'moderate' level, respectively.

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', then 401 and between 500 is considered 'severe'.

As per the Air Quality and Weather Bulletin for Delhi-NCR, the air quality is likely to be in the 'poor' category on December 10 and 11. And, it is likely to remain so till December 13 and deteriorate further to fall in the 'very poor' category on December 14 and 15, it added.

On the weather front, Delhi witnessed a shallow fog this morning with the maximum and minimum temperature settling at 23 degrees Celsius and 8 degrees Celsius respectively.

On Thursday evening, the national capital recorded a minimum temperature of 8.4 degree Celsius -- one notch below the average. According to India Meteorological Department (IMD), it was the lowest minimum temperature recorded in the month of December.

The relative humidity at 8.30 a.m. was recorded at 92 per cent.