About a dozen flights were on Wednesday delayed after a blanket of fog enveloped New Delhi [Images], also marginally bringing down the mercury to below 13 degree Celsius.

The airliners had to reschedule a number of flights to domestic destinations like Mumbai, Khajuraho, Patna and Tripura.

An airport official said the Runway Visibility Range dropped to 625 metres and the authorities had to use CAT-I landing system. He said as many as 10 flights were delayed because of the low runway visibility.

A Met department official said the foggy condition will continue for next couple of days as minimum temperature will plummet further.

The minimum temperature on Wednesday was 12.7 degree Celsius, which is almost four degree Celsius above normal in this time of the year.

On Tuesday, the minimum temperature was 13 degree Celsius while the maximum was 25 degree Celsius. The gradual rise in temperature is attributed to the arrival of western disturbances in the system.

The temperature is likely to fall in the next few days, the weatherman said.

The capital is expected to experience mainly clear sky in the next few days. However, there will be a drop of two-three degree Celsius in the night temperature on Thursday, he said.