New Delhi, Nov 26 : After a day of recording satisfactory to moderate level of PM 2.5 and PM 10 pollutants in the air, Delhi-NCR on Friday registered an overall Air Quality Index (AQI) of 380 with both the pollutants again falling to the 'very poor' category, according to System of Air Quality and Weather Forecasting And Research (SAFAR) estimates. "The air quality over Delhi-NCT is likely to remain in the upper end of 'Very Poor' category on November 26 and may reach in the lower end of 'Severe' category. Mostly calm or slow winds during night are unfavourable for effective dispersion of pollutants. The air quality is likely to improve marginally but remain in the upper end of 'Very Poor' category on November 27 and November 28," bulletin issued by Air Quality Early Warning System for Delhi (Ministry of Earth Sciences) read. The air quality is likely to remain in the 'very poor' category. Gradual improvement is likely from November 27 till November 30 and PM2.5 is to be the predominant pollutant. 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'. "The predominant surface wind is likely to be coming from the Southeast/East direction of Delhi with wind speed of 6 kmph, mainly clear sky and shallow fog in the morning on November 27. The predominant surface wind is likely to be coming from variable directions of Delhi with wind speed of 6 kmph, mainly clear sky and shallow fog in the morning on November 28. Winds are likely to be relatively strong during November 29 and 30," the bulletin added. India Meteorological Department (IMD) predicted a mainly clear sky with a misty morning on Friday. The maximum temperature for the day has been pegged at 28 degrees Celsius and minimum at 11 degree Celsius. On Thursday, the maximum temperature was recorded at 27.8 degrees Celsius and minimum at 11 degrees Celsius. The relative humidity at 8.30 a.m. was recorded at 95 per cent. /IANS