Siliguri Corridor
Siliguri Corridor (source: Wikipedia)Also known as Chicken's Neck, it is a narrow passage to India's eight northeastern states around the city of Siliguri. It is about 60 kms in length but only 22 kms in width at its narrowest point, plain terrain not interspersed with any natural obstacle. The countries of Nepal and Bangladesh lie on each side of the corridor and the Kingdom of Bhutan lies at the northern end of the corridor.
Between Sikkim and Bhutan lies the Chumbi Valley, a dagger-like slice of Tibetan territory. The southern end of the Dolam plateau or Doklam triboundary area slopes into the corridor. At the narrowest stretch, the corridor is generally formed by the Mechi River in the east; Nepal's Bhadrapur lies on the banks of the river. Further north the Mechi Bridge connects Mechinagar.
All land transportation between the rest of India and its far northeastern states uses this corridor. The route has a major broad gauge railway line.
A Chinese military advance of less than 130 km would cut off Bhutan, part of West Bengal and all of North-East India, an area containing almost 50 million people. This situation arose during the war between India and China in 1962. The security threat to this corridor was heightened during the 2017 Doklam incident as well.