At least 67 trains were running late and six cancelled due to dense fog in parts of north India on Wednesday morning, a railway official said.
Out of the six cancelled trains, four of them were to depart on Wednesday while two were to depart on Thursday.
Apart from that, as many as 15 trains were rescheduled on Wednesday, the official said.
The trains cancelled on Wednesday included the Varanasi-Jodhpur Marudhar Express, New Delhi-Varanasi Kashi Vishwanath, Dehradun-Howrah Upsana Express and New Delhi-Rajendra Nagar Rajdhani Express.
Delhi Junction-Malda Town Farakka Express and New Delhi-Puri Express were cancelled for Thursday.