New Delhi, Nov 19 (IANS): The air quality in the national capital which was under very "poor category" on Saturday morning, improved to "poor category" as the day progressed.

According to the System of Air Quality and Weather Forecasting And Research (SAFAR), the city's overall Air Quality Index (AQI) was recorded at 303 on Saturday morning. However, the air quality later improved to 'Poor category' as the overall AQI reached 276.

As per the SAFAR, the concentration of both PM 2.5 and PM 10 was recorded at 276 and 177 under poor and moderate category, respectively.

The 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".

However, the AQI of Delhi's neighbouring city of NOIDA remained in "very poor category" with the PM2.5 concentration at 325 and the PM 10 concentration at 161 under "very poor" and "moderate" category, respectively.

While Gurugram's overall air quality has improved to the "moderate category" and the AQI was reported at 180 under the "moderate" category. The PM 2.5 and PM 10 concentration levels stood at 180 and 129, both under "moderate" category.

Meanwhile, Delhi recorded the coldest morning of this season with a minimum temperature of 9 degrees Celsius on Saturday.

According to India Meteorological Department (IMD), the minimum temperature was three notches below normal.