Delhi shivers at 3.5°C, AQI severe; flights, trains delayed

New Delhi: A thick layer of fog gripped Delhi NCR, as the city woke up to a chilly morning with the capital recording a minimum temperature of 3.5°C – four degrees below normal and the lowest minimum so far this season. Cold wave conditions intensified in the northern plains on Sunday, accompanied by ‘very dense’ fog (Representative Photo) On Saturday, Delhi recorded a temperature of 3.6°C and 3.9°C on Friday, making it three consecutive days night time temperature has dipped below 4°C.

Amazon Sale season is here! Splurge and save now! Click here Cold wave conditions intensified in the northern plains on Sunday, accompanied by ‘very dense’ fog, with zero visibility recorded at Palam for over four hours, from 5am onwards, impacting both rail and flight operations. The IMD classifies it as a ‘cold wave’ when the minimum is 4.5 degrees or more below the normal.

It can also be classified as a cold wave in the plains when the minimum reading is below 4 degrees Celsius for two consecutive days. Over 75 flights were delayed at Delhi’s Indira Gandhi International (IGI) airport on Sunday morning, with seven flights – six to Jaipur and one to Mumbai, also being diverted.

Northern Railway meanwhile said at least 22 trains were delayed by more than one hour on Sunday morning. Low temperatures and low wind speed over the last 48 hours, also led to Delhi’s air quality deteriorating to ‘severe’ for the first time this year. The average AQI at 9am on Sunday was 458 (severe) – a deterioration from Saturday’s reading of 399 (very poor).

The Commission for Air Quality Management (CAQM) is likely to hold a meeting today and can impose measures under stage 3 (severe) and stage 4 (severe plus) categories of the Graded Response Action Plan (GRAP). The dip in minimum temperature over the last three days has been down to the upper level fog gradually dissipating from parts of northwest, central and east India, which has brought clear skies once more after nearly two weeks.

When upper level fog or cloudiness prevails over a region, the maximum temperature is low, as sunlight does not penetrate down to the surface. In such a situation, the minimum is usually higher than normal, as heat cannot escape into the atmosphere at night. A clear sky has the opposite effect, making days warm as ample sunshine reaches the surface.

The same heat is lost equally quickly at night – as there is no fog or cloudiness to stop it “We are now seeing the impact of clear skies, with dense fog now forming close to the surface again, making for low visibility. Until last week, we had improved surface level visibility, as the recent fog was forming in the upper levels of the atmosphere, thus blocking sunlight even during the day.” said an IMD official.

The maximum at Safdarjung, representative of Delhi’s weather, on Saturday, was 18.1 degrees, two degrees below normal. It was 19.3 degrees on Friday and 18.1 degrees on Thursday. The IMD has urged commuters on highways to exercise extreme caution and use fog lights during their journeys. The weather department has issued an orange alert for Sunday and Monday, forecasting dense to very dense fog with coldwave conditions.

The maximum is likely to remain around 18 degrees both today and tomorrow, with the minimum likely to hover around four degrees on Monday as well. SHARE THIS ARTICLE ON Share this article Share Via Copy Link Cold Wave Fog.