New Delhi: fog

More than 30 flights were delayed and several trains were running late as a thick blanket of fog enveloped Delhi and nearby regions on Monday morning.

The minimum temperature in Delhi was recorded at 4.2 degrees Celsius,  making this the coldest December 22 in the last five
years and also the lowest this season

Visibility was at less than 50 metres, causing trouble for schoolchildren and early office-goers.

Read more:

http://www.hindustantimes.com/india-news/newdelhi/dense-fog-envelops-delhi-3-dozen-flights-hit-trains-running-late/article1-1298974.aspx