NEW DELHI: Dense fog enveloped Delhi's Palam and Safdarjung on Thursday - the third dense fog spell that kept the visibility to around 50-100 metres till 7.30 am. The city is likely to see dense fog over the next two days as well, officials in the India Meteorological Department (IMD) said.
Senior IMD scientist RK Jenamani said that Palam saw dense fog cover from 4.30 am with visibility going down to 50 metres till 7.30 am. "At Safdarjung, the visibility reduced to 100 metres since 7 in the morning," he said.
According to IMD officials, this is the first prolonged spell of fog this winter has seen so far in the entire northern plains. "Dense fog is likely over Delhi-NCR over the next two days as well while it will reduce to 'moderate' from January 16-19. After January 20, shallow fog is likely," he said.
Delhi on Wednesday saw a moderate fog cover with the visibility at Palam being less than 500 metres till 8.30 am while Safdarjung saw shallow fog with visibility remaining around 800 metres. Delhi on Tuesday recorded its second 'dense fog' spell of the season with visibility dropping to 50 metres at Indira Gandhi International (IGI) airport 5 am onwards, delaying operations.
As per officials, fog cover reduced from Tuesday, but resurfaced on Thursday because of high-moisture content and low minimum temperature.
IMD classifies fog to be 'dense' when visibility drops below 200 metres, while it is said to be 'very dense' when it drops below 50 metres. A visibility between 200 and 500 metres is “moderate” while between 500 and 1000 metres is classified as "shallow" fog.
"Cold northwesterly winds are blowing over the city. However, clouds are likely to resurface with two more WDs likely to hit the Western Himalayan Region around January 16 and then on January 18, which will have an impact on The city and the entire northern plains. These will again bring moisture and will not allow the mercury to drop below normal," a senior official said.
On Thursday, the minimum temperature was 5.8 degrees C, two notches below the season's average while the minimum settled at 16.7 degrees C, three notches below normal for this time of the year.
January 13 Weather Report
Temperature
5.80 degree Celsius two notches below the season’s average
16.70 degree Celsius three notches below normal
83 per cent relative humidity at 5.30 pm
Fog Blanket
Visibility dropped to 100 metres at Safdarjung Observatory and 50-100 metres at Palam Observatory
Air Quality Index (AQI) levels
According to the Central Pollution Control Board (CPCB), Delhi's air quality deteriorated from 290 in the morning, to 'poor category' and 'very poor' category by 4 pm.