With the mercury dipping many notches below normal, the national capital recorded the coldest day of the season on Wednesday. The minimum temperature dropped to 4.9 degrees Celsius - five degrees below the normal for this time of year.

"The minimum temperature of 4.9 degrees Celsius reported over Safdarjung is the lowest minimum of this winter season. The same minimum temperature of 4.9 degrees Celsius was reported last year also, on 15th December," said the India Meteorological Department (IMD), as reported by news agency PTI.

The relative humidity stood at 64% at 8:30 am. The mercury was expected to rise to around 23°C by the afternoon.

Meanwhile, Delhi's air quality continued to remain in the 'poor' category. The city's air quality index (AQI) was recorded at 207 at 10 am - an improvement from the previous day's reading of 223.

According to the Central Pollution Control Board (CPCB), an AQI of 0-50 is classified as 'good', 51-100 as 'satisfactory', 101-200 as 'moderate', 201-300 as 'poor', 301-400 as 'very poor' and above 400 as 'severe'.

Out of the 39 monitoring stations across the national capital, only RK Puram registered an AQI in the 'severe' category. Twenty-three stations reported 'poor' air quality. The remaining stations recorded 'moderate' air quality, according to data from the Sameer app, which provides hourly updates.

The IMD also forecast that the cold conditions would not be limited to Delhi but could affect other northern states such western Uttar Pradesh, Haryana and Punjab through December 14, India Today reported.