Delhi wrapped in dense fog as temperature drops to 5.6ºC, air quality very poor

Met officials said low visibility conditions are likely to last for another day due to moisture-rich winds blowing from Agra, Meerut side.

delhi Updated: Jan 17, 2018 11:06 IST
Aruveetil Mariyam Alavi
Aruveetil Mariyam Alavi
Hindustan Times
Delhi weather,Delhi fog,Delhi smog
The city’s average air quality index (AQI) on a scale of 500, was a ‘very poor’ 304.(Arvind Yadav / HT Photo)

Wednesday saw one of those cold, foggy and polluted mornings in Delhi. Motorists were seen switching on their blinkers in parts of the city where they could not see beyond 200m.

Train operations were also affected. At least 21 inbound trains were late, four were rescheduled and 13 were cancelled, as of 6am on Wednesday, according to the Northern Railways.

The mercury dropped to 5.6 degrees Celsius on Wednesday morning, which is lesser that the average temperature for this time of the year — 7.1 degrees Celsius. “Tuesday was clear sky, and hence a lot of the heat radiation from the earth was lost. This explains why Wednesday was colder,” said Kuldeep Srivastava, a senior scientist with the regional weather forecasting centre (RWFC). However, at Palam station, the visibility was around 600 to 650m.

Drier and stronger north-westerly winds gave way to calmer, moisture rich winds coming in from the Agra, Meerut side on Wednesday.This moisture rich wind, coupled with the lowered temperatures, have caused dense fog in the city, according to Srivastava. According to the Met office, visibility had dropped to 200 metres at Safdarjung, at around 8.30am on Wednesday.

Heavy fog near ITO on Wednesday. (Arvind Yadav / HT Photo)

With calmer winds, and increased moisture in the air, pollution levels also seem to have spiked in the city.

Earlier this week, Delhi benefitted from strong winds blowing at 15km /hour. By Wednesday morning, the wind speed had calmed down to 10kmph. Winds help flush out the pollutants and the air quality improved from ‘very poor’ category to ‘poor’ category on Tuesday, but on Wednesday morning, it had spiked back up to ‘very poor.’

The city’s average air quality index (AQI) — a measure of pollutants in the air on a scale of 500 — was a ‘very poor’ 304. While most individual stations in Delhi recorded either poor or very poor air quality, areas close to Shadipur had it worse. The AQI here had reached severe levels, at 409. The primary pollutant here was the smaller and more dangerous particulate matter, PM 2.5.

Of the lot, Mandir Marg and neighbouring areas had the cleanest air in Delhi, with AQI dropping to a ‘poor’ 211 here. The primary pollutant was the larger PM10.

According to the IMD the morning temperatures will range between 6 and 7 degrees Celsius until Monday, with the possibility of some fog. The dense fog is only expected to persist for another day, before giving way to shallow fog and then later mist. On Tuesday, the minimum temperature will rise to nine degrees Celsius, and there is also the possibility of some rain then.

First Published: Jan 17, 2018 10:08 IST