Delhi's minimum temperature rose slightly to 5.5 degrees Celsius on Monday under the influence of a fresh western disturbance affecting the upper reaches of the Himalayas. “This a fast-moving Western Disturbance (WD) and it will withdraw on Tuesday. Thereafter, the temperatures are expected to drop again,” Mahesh Palawat, an expert at Skymet Weather, a private forecasting agency, said.
The WD will lead to a light to moderate snowfall in the upper reaches of Jammu and Kashmir, Ladakh and Himachal Pradesh, he said.
The India Meteorological Department said the Safdarjung Observatory recorded a minimum of 5.5 degrees Celsius on Monday morning as against 3.4 degrees Celsius on Sunday, the lowest this season so far.
It has predicted cold wave conditions at some place in the city from December 23 to December 26.
Moderate to dense fog is also predicted during the period, it said.
For the plains, the IMD declares a cold wave when the minimum temperature is 10 degrees Celsius or below and is 4.5 notches less than normal for two consecutive days.
However, for small areas such as Delhi, a cold wave can be declared if the criteria are fulfilled even for a day, officials said.
The air quality was recorded in the "very poor" category.
The city's air quality index (AQI) was 323 at 10 am. The 24-hour average AQI was 321 on Sunday.
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".