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Visibility below 100m amid season’s first ‘dense’ fog spell in Delhi
While no flight cancellations or diversions were reported at Delhi’s Indira Gandhi International (IGI) Airport, some flights were delayed during this one hour-window.
Delhi recorded its first “dense” fog spell of the winter season, with visibility dropping below 100 metres at Palam on Wednesday between 9am and 10am.
The IMD classifies fog to be “dense” when visibility drops below 200 metres, while it is classified as “very dense” when it drops below 50 metres. Visibility between 200 and 500 metres is “moderate” while between 500 and 1,000 metres is “shallow” fog. Delhi is expected to record “moderate” fog on Thursday as well, with isolated parts recording “dense” fog.
“Visibility was down to 100 metres at Palam between 9 and 10am, while “shallow” fog was recorded at Safdarjung. This is the first “dense” fog spell of this winter season and fog intensity is expected to remain high for the next few days,” says RK Jenamani, scientist at India Meteorological Department.
While no flight cancellations or diversions were reported at Delhi’s Indira Gandhi International (IGI) Airport, some flights were delayed during this one hour-window.
An airport official, requesting anonymity, confirmed there were minimal delays due to the fog, with no cancellations or diversions reported either. “Some flights were delayed, but the impact was only for around an hour. During this period, flight operations functioned smoothly,” the official said.
Due to increased moisture in Delhi’s air after Tuesday’s light rain, the Capital’s air quality improved to “poor” with the Air Quality Index (AQI) recording a reading of 267 -- down from Tuesday’s reading of 305 (very poor).
An AQI reading between 201 and 300 is considered “poor”, 301 and 400 “very poor”, and 401 and 500 “severe”.
Delhi recorded a minimum temperature of 8.4 degrees Celsius on Wednesday – one degree above normal– while the maximum was 21.2 degrees, also one degree above normal for this time of the season.
Jenamani said the minimum temperature could hover between 5 and 6 degrees Celsius for the next two days, with the maximum temperature settling at around 21 degrees Celsius.
“Another western disturbance is expected to influence northwest India in the next two or three days, which will bring coldwave conditions to Punjab, Haryana and Chandigarh between December 30 and January 1; however, the impact in Delhi will not be much and the minimum could hover around 5 to 6 degrees Celsius,” Jenamani said.
Delhi’s air quality is expected to hover between the “poor” and “moderate” categories in the next few days.
According to the System of Air Quality and Weather Forecasting And Research (Safar), a forecasting body, wind speed will remain high on December 30, 31 and January 1, allowing air quality to improve further.
“Delhi’s AQI has improved due to Tuesday’s rain but is still within the ‘poor’ category. Relatively high wind speeds are likely for the next three days (December 30, 31, January 1), enhancing ventilation and affecting AQI to be in the lower end of the ‘poor’ to ‘moderate’ category,” said Safar.
