Delhi sees season’s first fog as air quality falls to ‘moderate’ category

Following the spell of rain from October 7 to 11, there is high moisture content in the air, with clear skies aiding the formation of early morning fog, India Meteorological Department (IMD) officials said

The national Capital witnessed this winter season’s first fog spell on Wednesday morning as visibility fell to 350 metres in parts of Delhi.

Delhi’s maximum temperature is meanwhile expected to be around 31°C during the day. (File image (Representative picture))

Following the spell of rain from October 7 to 11, there is high moisture content in the air, with clear skies aiding the formation of early morning fog, India Meteorological Department (IMD) officials said.

“This is the season’s first fog spell. Visibility dipped to around 350 metres at Palam and this is because of the high moisture content that is available in the atmosphere. As rains stop and wind conditions become calm, fog can form in the northern plains,” said RK Jenamani, scientist at IMD.

Delhi recorded a minimum temperature of 20.2°C on Wednesday, which is around normal for this time of the year.

Delhi’s maximum temperature is meanwhile expected to be around 31°C during the day.

Visibility at the Palam station was down to around 350 metres between 7am and 8:30 am, while it was recorded at around 600 metres during this period at Safdarjung.

The IMD classifies fog as ‘shallow’ when visibility is between 500 and 1000 metres, as ‘moderate’ when it is between 200 and 500 metres and as ‘dense’ when it is 200 metres or lower.

Owing to this fog, Delhi’s air quality has also deteriorated on Wednesday morning, touching the ‘moderate’ category.

Delhi’s overall air quality index (AQI) which was recorded as 66 (satisfactory) at 4pm on Tuesday, had touched a reading of 125 (moderate) by noon by Wednesday.

Met officials say with wind speeds dropping and fog prevailing over the region, the moisture was able to trap local emissions. “As the sun comes out, AQI will once again improve,” the official said.