The minimum temperature in Delhi dropped to 5.7 degrees Celsius on Sunday but it is likely to rise over the next two days due to a change in the wind direction, the India Meteorological Department (IMD) said. The national capital had recorded a low of 6.6 degrees Celsius on Saturday.

The Safdarjung Observatory, which provides representative data for the city, recorded a minimum temperature of 5.7 degrees Celsius this morning. An IMD official said easterly winds are blowing in Delhi that are not as cold as northwesterly winds coming in from the snow-clad western Himalayas.

Hence, the minimum temperature is likely to rise by a few notches over the next two days. It is expected to rise to 8 degrees Celsius on Monday, the official said. Delhi's air quality index (AQI) improved slightly to the 'very poor' category from 'severe' on Saturday as favourable wind speed helped in dispersion of pollutants.

The city's AQI was 347 at 9 am. The 24-hour average AQI was 407 on Saturday, 460 on Friday, 429 on Thursday, and 354 on Wednesday. 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', and 401 and 500 'severe'.

Delhi's AQI remained in the 'severe' category for three consecutive days till Saturday due to "extremely unfavourable" conditions for dispersion of pollutants.