Dense fog enveloped the Indian capital for the second day in a row on Tuesday, disrupting air and train services, officials said. "At least 35 flights, 22 domestic flights and 13 international flights, to and from the national capital's Indira Gandhi International Airport have been delayed this morning as runway visibility was very low. But, no flight has been canceled yet," a senior aviation official said. Fog also hit train services as some 17 trains to and from the Indian capital have been delayed, a senior Indian Railways official said. Fog had hit air and rail traffic Monday but normalized during the course of the day. The Indian Meteorological department has predicted more cold and foggy days ahead, and rain on Christmas Day. It has said that the temperature may drop heavily on New Year's day. Fog is common in northern India during the severe winter months of December and January, often leading to disruption of flights and trains.