A major landslide, triggered by heavy rains, on the National Highway 10 cut off Sikkim from the rest of the country on Wednesday morning, officials said.
The landslide happened at the 29 Mile area in West Bengal, they said.
The NH-10, which is considered the lifeline for the people of Sikkim, is maintained by the General Reserve Engineer Force (GREF) and the PWD of West Bengal, they added.
Officials at the site said that it will take at least a day or two to clear the debris completely.
The road can be cleared for one way traffic by evening which is possible if the rain subsides, they said.
Drivers ferrying essential commodities to Sikkim from Siliguri are stuck at the spot.
Travelling on this highway during heavy rains is dangerous as there are many trouble spots along it, officials said.
