Delhi reeled under a cold wave on Tuesday as icy winds sweeping through the city brought the minimum temperature down to 3.6 degrees Celsius, the India Meteorological Department (IMD) said.

The Safdarjung Observatory, which provides representative data for the city, recorded a low of 3.6 degrees Celsius as against 5.6 degrees Celsius on Monday.

The weather stations at Ayanagar and Lodhi Road recorded a low of 2.6 degrees Celsius and 2.7 degrees Celsius respectively, it added.

In the plains, the IMD declares a cold wave if the minimum temperature dips to 4 degrees Celsius. A severe cold wave is when the minimum is 2 degrees Celsius or less.

The IDM said the mercury may drop further by New Year's Eve.

Cold wave conditions are predicted in parts of the city over the next three days, it said.

Kuldeep Srivastava, the head of the regional forecasting centre of the IMD, said a western disturbance led to "scattered to fairly widespread" snowfall in Jammu and Kashmir, Ladakh, Himachal Pradesh and Uttarakhand.

Cold and dry northerly/northwesterly winds from the western Himalayas have been barrelling through the plains, bringing the minimum temperature in north India down, he said.

On December 20, the Safdarjung Observatory had recorded a minimum of 3.4 degrees Celsius, the lowest this season so far.

Delhi's air quality was recorded in the "poor" category on Tuesday morning. The city's air quality index (AQI) was 237 at 9 am.

The 24-hour average was 253 on Monday, 396 on Sunday, 337 on Saturday, 357 on Friday, 423 on Thursday and 433 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".

Officials at IMD said favourable wind speed, up to 15 kmph, aided in the dispersion of pollutants.