NEW DELHI, Dec. 19 (Xinhua) -- Dense fog engulfed the Indian capital and its surrounding areas on Thursday morning as departures and arrivals of many flights and trains were delayed due to poor visibility.

Regular commuters faced difficulty driving on major highways since visibility was less than 50 meters at many places.

An advisory issued by the Delhi Airport said that low visibility procedures were implemented, and that there might be some flight disruptions. "Passengers are requested to contact the airline concerned for updated flight information," it added.

"IndiGo," a private airline also alerted its passengers about delays in departures from the Delhi Airport. "Due to poor visibility, there have been delays in flight departures/arrivals across the network. Do keep a track of your flight status," it tweeted.

December and January are harsh winter months in India, as mercury dips to its lowest particularly in Delhi and other parts of north India coupled with cold waves, thereby leaving people, particularly the homeless, shivering in cold.

Over the past couple of days, temperature has dipped to below 10 degrees centigrade in Delhi and nearby areas.