: It was a cold foggy Christmas day in the Capital on Sunday, with the maximum temperature settling at 15.4 degrees Celsius, the coldest yet for the season.
The temperature was six degrees below normal for this time of the year, a significant fall from the sunny 24.5 degrees Celsius recorded the previous day. Shallow fog continued through the day, keeping Delhiites deprived of warm sunshine. The night, however, was warmer than usual with the minimum settling at 11.4 degrees Celsius.
Despite foggy conditions, flight operations at Indira Gandhi International Airport were not affected. Visibility at 8.30 a.m. was recorded at 600 metres, which dipped to 200-300 metres between 9 a.m. and 11 30 a.m. before improving.
Reversal of winds
“Due to reversal of winds from easterly to westerly at 9 a.m, there was intensification of fog across Delhi from forenoon, with wind speeds between 7 and 12 kmph,” said a Meteorological Department official.
The maximum temperature fell by almost 10 degrees during the day, as the city received no sunlight to warm the air or the surface due to the shallow fog, he added.
Incidentally, there was hardly a difference between the minimum and maximum temperatures, as the minimum recorded overnight was 11.4 degrees Celsius, said the weatherman.
Usually, the city experiences such conditions on two-three occasions every winter due to the influence of western disturbance, which cause similar wind reversal, bringing a blanket of fog later in the day.
Trains late
Railway officials informed that 80 Delhi-bound trains were running behind schedule by several hours, while 23 others required to be rescheduled owing to poor visibility. There was no fresh cancellation of services.
Forecast for fog
As per the forecast for Monday, the maximum and minimum are expected to hover around 21 degrees Celsius and 10 degrees Celsius respectively, with shallow to moderate fog in the morning. The extended observation shows that dense fog is likely to return during the last day of the year.
The air quality in the city was “very bad” with levels of toxic pollutants remaining several times over the safe limit.
Pollution unchanged
However, air pollution levels have been around the same over the past week, and the dip in temperatures, which was expected to worsen air quality, did not have a very dramatic impact.
According to the National Air Quality Index, the air quality index (AQI) as of 7 p.m. at Anand Vihar, Delhi Technological University and Siri Fort was above 401, putting it in the ‘severe’ category. Six locations — Shadipur, NSIT Dwarka, Mandir Marg, R.K. Puram, Punjabi Bagh and ITO — had ‘very poor’ AQIs, and one — IHBAS (Dilshad Garden) — had a ‘poor’ AQI.
As per the SAFAR index, the levels of both PM2.5 and PM10 remained at over four times the respective standards of 60 and 100 micrograms per cubic metre.
At 7 p.m, the 24-hour rolling average for PM2.5 was 273 micrograms per cubic metre, or ‘severe’, while the level of PM10 was 428 micrograms per cubic metre, or ‘very poor’.
