Fog, rain and chill prevail in Delhi; mercury may dip again on Monday

Delhi woke up to another cold morning full of fog and light winds on Saturday, which became colder still by evening as several parts of the city received light rain due to an interaction between a western disturbance and easterly winds. There were no diversions or cancellations in flight schedules at the Indira Gandhi International Airport due to the fog, and the rain did not have any meaningful impact on the air quality, which remained in the “very poor” category. There will be light rain in the early hours of Sunday as well, according to the India Meteorological Department (IMD).

The maximum temperature went down by 0.6 degrees Celsius (°C) and was recorded at 17°C, 2.9°C below the normal and a slight drop from 17.6°C recorded the day before. The minimum temperature saw a slight increase and was recorded at 7.7°C, 0.3°C above the normal and up from 6°C on Friday, which was higher than the 4.8°C recorded on Thursday. IMD has forecast the maximum and minimum temperatures to be 17°C and 11°C respectively on Sunday.

“A moderate fog might form in the morning of Sunday. No significant rain is expected. The influence of the western disturbance will reduce and northwesterlies are likely to start blowing the refion from Monday, leading to a dip in minimum again,” said Mahesh Palawat, vice president at Skymet.

Rain

While the early hours of the day logged no rain, several parts of Delhi started experiencing light rain from 2.30pm onwards. Between 2.30pm and 8.30pm, Safdarjung received 2.2mm of rain, Palam 3.4mm, Lodhi Road 0.5mm, Ridge 0.7mm, Ayanagar 1.2 mm, Delhi University 2.5mm, Pusa 2mm, Narela 0.5mm, Najafgarh 5.5mm and Pitampura 2mm.

Fog

Zero visibility prevailed over Palam from 11.30pm on Friday to 2am on Saturday. The visibility improved to 500m by 7 am. Safdarjung, representative of Delhi’s weather, observed a minimum visibility of 50m between 12.20am and 1.30am, which improved to 200m by 7.30 am

“The easterlies in the early hours when there was zero visibility was 6-8km/hr. The speed of the east-southeasterlies increased to 15-18km/hr, thus improving the visibility,” said an IMD official.

IMD has issued a yellow alert for Monday and Tuesday, warning people of a moderate fog in many places and a dense fog in isolated places.

IMD classifies it as a shallow fog when visibility is between 500m and 1,000m, moderate when it is between 200m and 500m, dense fog when visibility ranges from 50m to 200m, and very dense fog when visibility falls below 50m.

According to airport authorities, no flight diversions or cancellations were reported as of 9 am on Saturday.

Air quality

The 24-hour average air quality index (AQI) of the city was recorded at 327 (very poor) at 4pm, according to Central Pollution Control Board’s (CPCB) data, a slight improvement from 397 recorded at 4pm on Friday. The 24-hour average AQI, however, only became available around 11pm due to a server issue, according to an official from the Commission for Air Quality Management (CAQM).

According to Delhi’s Air Quality Early Warning System (AQEWS), air quality is likely to improve to poor by Sunday and then deteriorate to very poor by Tuesday again.

“The air quality is likely to be in the poor category from Sunday to Monday, and in the very poor category on Tuesday. The outlook for the next six days is that the air quality is likely to be in the poor to very poor category,” the AWEWS bulletin said on Saturday evening.