Delhi's air quality continued to oscillate between 'poor' and 'very poor' categories Saturday due to increased pollutant holding capacity of air after rainfall and stubble burning in neighbouring states. Air pollution level is on the path of reversal. It has increased after the impact of rain got over and the AQI is entering the 'very poor' range, the Centre-run System of Air Quality and Weather Forecasting (SAFAR) said. Also Read| Himachal Pradesh Weather: State reels under severe cold after snow The overall air quality index (AQI) was recorded at 309, which comes under 'very poor' category, according to the SAFAR. Central Pollution Control Board (CPCB) data showed the overall AQI at a 'poor' 258. On Saturday, the PM2.5 \u2014 particles in the air with a diameter of less than 2.5 micrometres \u2014 level was recorded at 122, while the PM10 level was recorded at 228, according to Central Pollution Control Board data. Delhi's air quality showed significant improvement on Wednesday and Thursday after rain washed away the pollutants but the rainfall also led to an increase in air capacity to hold pollutants, SAFAR said. Also Read| Jammu and Kashmir: Minimum temperatures drop across the state "Although wind speed is better (higher) but holding capacity (of air) is also high due to moisture, which is unfavourable," the SAFAR said in a report. Fire counts from stubble burning increased in past 24 hours, which may contribute 8-10 per cent to Delhi pollution, the report said.\u00a0 An AQI between 0 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'. According to CPCB data, three areas in Delhi recorded 'very poor' air quality and 31 recorded 'poor' air quality. n India Meteorological Department (IMD) official said.