Delhi-NCR residents on Monday woke up to another cold morning as the minimum temperature dropped below 5 degrees Celsius for the second consecutive day.

According to the India Meteorological Department (IMD), the national capital registered a minimum temperature of 4.5 degrees Celsius at 5.30 am. Earlier on December 15, Delhi-NCR also witnessed a minimum temperature of 4.9 degrees Celsius. At Najafgarh, the minimum temperature was slightly higher, at 6.2 degrees Celsius.

In the coming days, Delhi may witness a further increase in the cold wave with shallow fog in various parts due to calm winds and high humidity, as the IMD.

The weather department has also issued a cold wave warning for certain states of northern India, including Jammu and Kashmir, Punjab, Haryana, and western Uttar Pradesh, among other states.

A cold wave is officially declared in the plains when the minimum temperature falls to 4 degrees Celsius or below, or when it registers a drop of 4.5 to 6.4 degrees from normal. With temperatures hovering around these thresholds, the capital has seen biting cold mornings, forcing residents to bundle up against the chill.

Amidst the intense cold conditions, the air quality in Delhi and surrounding areas also deteriorated to the ‘very poor’ category on Monday due to unfavourable weather conditions and low wind speeds.

According to the Central Pollution Control Board, the overall Air Quality Index (AQI) for the national capital was recorded at 334 at 4 am on Monday.

The air quality slipped to the ‘very poor’ category on Sunday evening, with the AQI climbing to 307, up from 294 just hours earlier, which was at the higher end of the ‘poor’ category.

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’.