Around 25 trains were delayed, 12 rescheduled and 1 cancelled in Delhi on Wednesday due to decreased visibility/operational reasons. Several parts of Northern India, including Delhi-NCR, experience foggy mornings every year during winters. This severely affects the movement of trains and flight operations. According to Skymet Weather, in absence of any significant weather system, dry and cold northwesterly winds from the snow-clad Himalayas have been blowing across Rajasthan, Punjab, Haryana, Uttar Pradesh and Delhi-NCR. Earlier this month, the air pollution level peaked in Delhi-NCR breaching the 'severe' level as per the Air Quality Index