NEW DELHI - A dense smog engulfed the Indian capital territory and outskirts Thursday morning, disrupting flight operations and train schedules.

Low visibility procedures were in progress at Delhi airport, and passengers were requested to contact the airline concerned for updated flight information, the airport operator said.

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A private airline, IndiGo, said in a statement Thursday morning that winter fog may impact flights to and from Amritsar, Varanasi and Delhi. The airline urged passengers to monitor their flight status before heading to the airport.

According to Flightradar 24, over 300 flights have been delayed at Delhi airport.

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Meanwhile, the city's air quality Thursday saw a further dip and continued to be in the severe category for the second straight day.

Industrial activities and vehicular traffic are significant contributors to air pollution in the city, along with rampant construction.