Chandigarh, Dec. 18 -- Three departure flights were cancelled and two arrivals were diverted as Chandigarh experienced the first spell of dense fog on Wednesday when visibility dropped to as low as 150 metres. As per India Meteorological Department (IMD), fog season has officially started in the city and is expected to get worse in the coming days. An orange alert has been issued for Thursday and Friday.

As per the IMD observatory in Sector 39, the visibility at 5.30 am was 800 metres which plunged to 150 metres by 8.30 am before improving to 3,500 metres by 11.30 am. Fog is considered to be dense when visibility drops between 50 metres to 200 metres. Below 50 metres, it is classified as very dense while visibility between 200 metres and...