A dense fog wrapped the national capital and surrounding areas Wednesday morning as cold wave conditions persisted in northern India. The visibility dropped to zero in several places, posing to a risk to rail and flight operations. In Delhi, zero visibility was observed over Palam since 4:30 am. The weather office has predicted fog again in the city in evening and night. Delhi recorded temperature at 10 degrees Celsius around 5:30 am. Flights operations are normal in Delhi, but the airport has asked passengers to contact the airlines for updated flight information.