Dense fog cover over the national capital delayed 115 trains Thursday, an official said.An official of the Northern Railway said the arrival of 91 trains to the city was delayed, while 24 trains leaving the capital city were rescheduled due to dense fog.The Met Office said the visibility slumped to 100 metres in the morning.The minimum temperature of the day was 5 degrees Celsius, three notches below the season's average."There was dense fog in the morning. The day is likely to be clear, but fog may return in the evening," said an official of the India Meteorological Department.The day's maximum temperature is likely to hover around 16 degrees Celsius.Humidity at 8.30 a.m. was 91 percent.Wednesday's minimum temperature settled at 5 degrees, three notches below the season's average, while the maximum was 15.9 degrees Celsius, six notches below the season's average.