Dense fog blanketed most of the Tarai districts on Monday, with poor visibility affecting vehicular movement along the major highways and disrupting at least two domestic flights.

Foggy conditions for the past few days have also resulted in a sharp drop in morning and evening temperatures.

In Biratnagar, a man died due to cold, according to police. A rickshaw puller in his 40s was found unconscious in Jaljala Chowk in Biratnagar, said police, adding that he died while undergoing treatment at the Koshi Zonal Hospital.

According to police offices in Sunsari and Chitwan, poor visibility due to dense fog resulted in a vehicular collision along the highway in which at least three people were killed on Monday. In Sunsari, at least six road accidents due to fog and poor visibility were reported in the last 24 hours, police said.

On Sunday night, according to traffic police, a truck driver died when his vehicle hit another truck from behind in Ghopali Tole of Itahari. The accident took place due to poor visibility, said traffic police.

Two domestic flights of Buddha Air and Yeti Airlines in the Kathmandu-Janakpur sector were also cancelled due to bad weather.

Distribution of moisture in the atmosphere brought by the scattered winter rains last week caused foggy conditions with a sharp drop in morning and night temperatures in many places along the Tarai plains, said Barun Paudel, a meteorologist at the Meteorological Forecasting Division (MFD) on Monday. Many high-altitude areas, including Kalinchowk and Kharidhunga of Dolakha district, grappled with cold conditions as temperatures dropped to below freezing.

“There will be dense foggy mornings with improvement during the evenings before getting foggy again during nights for the next couple of days until another winter rain system enters the country,” said Paudel.

A locally developed low pressure system in and around the Kathmandu Valley resulted in cloudy weather condition with drizzle in hilly areas surrounding the Valley on Monday. Jumla recorded the lowest temperature at minus 5 degrees Celsius, followed by Jomsom and Jiri at minus 2 and minus 1 degrees Celsius, according to the MFD. Kathmandu recorded minimum temperature of 3.6 degrees Celsius.