New Delhi, Dec 5 (IANS): Air pollution levels in Delhi-NCR remained a cause for worry as the Air Quality Index (AQI) on Wednesday recorded 'very poor' rating across many areas of the national capital.

"Overall air quality over Delhi continues to remain in the very poor range. It may improve a few notches on Thursday, but will remain in the same category," said System of Air Quality and Weather Forecasting And Research (SAFAR) in its daily pollution analysis.

The AQI of Delhi was recorded at 331 with Faridabad, Greater Noida and Noida accompanying it in the 'very poor' category. Ghaziabad, meanwhile, fell into the 'severe' category with an AQI of 406. Gurugram maintained its 'poor' air quality with its AQI at 231.

With no impact of stubble burning now, SAFAR said that moderate wind speed is the only weather factor which is not allowing pollution to accumulate.

"Rest of the weather conditions such as high humidity and low ventilation are unfavourable for the air quality," it said.

Meanwhile, Director of a private weather agency Skymet Mahesh Palawat warned of deteriorating air quality over North India between December 9 and 10 due to "western disturbances which might bring more moisture in the air".

According to CPCB data, PM2.5 at 8 p.m. was 178 and PM10 at the same time was 346.

With current pollution situation, official agencies suggested wearing N-95 or P-100 respiratory masks while going out. They also cautioned against morning walks and exercises.