Dense fog reels Delhi; AQI remains 'very poor'

New Delhi, Feb 20: People from the national capital woke up to "dense to very dense fog" on Saturday with the minimum temperature settling at 10.4 degrees Celsius, as per the Meteorological department. The air quality in Delhi remained in the "very poor" category with Air Quality Index (AQI) docking at 309 and likely to improve on Sunday (tomorrow), according to the System of Air Quality and Weather Forecasting And Research (SAFAR).

The visibility at Palam was reported at 0 metres and Safdarjung had visibility of 100 metres. The humidity was recorded at 100 per cent at 8.30 am.

According to the IMD, a "very dense" fog is when the visibility is between 0 and 50 metres. In the case of "dense" fog, the visibility is between 51 and 200 metres, "moderate" 201 and 500 metres, and "shallow" 501 and 1,000 metres.

It is repoetedly said that the maximum temperature is expected to hover around 26 degrees Celsius on Saturday. On Friday, the maximum temperature settled at 27.8 degrees Celsius, while the minimum temperature was 9.6 degrees Celsius.

"The overall Delhi air quality is in the low-end of the Very Poor category as forecasted. Surface winds are low and forecasted to improve. A fresh western disturbance is likely to affect the Delhi region from February 21. A marginal improvement in ventilation and lower end of Very poor AQI is forecasted for tomorrow. AQI is likely to improve Very Poor to Poor on February 21 and further improve to Poor on February 22," SAFAR said in its bulletin.

An AQI between 0-50 is marked good, 51-100 is satisfactory, 101- 200 is moderate, 201- 300 is poor, 301-400 is very poor and 401-500 is considered severe.