Cold wave conditions are likely to return over Delhi for the next 4 days as predicted by the Indian Meteorological Department (IMD). The temperature in the capital is expected to stay at 3-4 degree Celsius with moderate to dense fog conditions during the period.
The Safdarjung Observatory, which provides representative data for the city recorded a minimum of 3.4 degree Celsius on Sunday, the lowest this season so far. The conditions got better by Tuesday when the lowest temperature was recorded at 5.3 degree Celsius, the observatory reported.
The rise in minimum temperature after the initial cold wave was credited the Western Disturbance (WD) which affected the upper reaches of Himalayas. The maximum temperature settled at 23.5 degrees Celsius, two notches more than normal.
"After the WD withdraws on Tuesday, the temperatures are expected to drop again," Mahesh Palawat, an expert at Skymet Weather, a private forecasting agency, said.
Another Western Disturbance is likely to affect the upper Himalayan region from December 26, Palawat 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 city's air quality index (AQI) was 365 at 9 am. The 24-hour average AQI was 332 on Monday and 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".
