Siliguri Corridor

The Siliguri Corridor is a narrow stretch of land (about wide) located around the city of Siliguri in West Bengal, India. The corridor is important as it connects the states of Northeast India to the rest of India through the city of Siliguri. 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. The Kingdom of Sikkim formerly lay on the northern side of the corridor, until its merging with India in 1975.
The city of Siliguri, in the state of West Bengal, is the major city in this area and the central transfer point that connects Bhutan, Nepal, Bangladesh, Sikkim, Darjeeling, and Northeast India to one another.
History.
The Siliguri Corridor was created in 1947 after the partition of Bengal. The kingdom of Sikkim formerly lay on the northern side of the corridor, until its union with India in 1975 via a publicly held referendum. This gave India a buffer to the north of the Siliguri Corridor and consolidated India's control over the western side of the Chumbi Valley.
Geostrategic importance.
The Siliguri Corridor is an especially important and sensitive territory for India, formed by the creation of East Pakistan (now Bangladesh) in 1948. The partition of India occurred as a result of hostility between the Indian National Congress and the Muslim League. From the very beginning, the relationship between these two new states was marked by hostilities and confrontations.
The formation of East Bengal created a geographical barrier to the northeastern part of India. The narrow Siliguri Corridor, which at one point is less than wide, remained as the only bridge between the northeastern part of India and the rest of the country.
Wedged between Bangladesh to the south and west and China to the north, the region has no access to the sea closer than Kolkata, on the other side of the corridor. Between Sikkim and Bhutan lies the Chumbi Valley, a dagger-like slice of Tibetan territory. A Chinese military advance of less than 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.
India has embarked on a slew of projects, such as construction of India-China Border Roads and Advance Landing Ground (AGLs), Northeastern India connectivity and Look-East transnational connectivity projects to create multiple alternatives to Silliguri corridor, including through Bangladesh and sea, to mitigate the risk of being cut off.
Current situation.
As a sensitive area amidst three countries, the strip is heavily patrolled by the Indian Army, the Assam Rifles, the Border Security Force and the West Bengal Police.
All land transportation between rest of India and its far northeastern states uses this circuitous corridor, as there is no free-trade agreement between Bangladesh and India. The Tetulia Corridor, an alternative to the Siliguri Corridor, is proposed under Article VIII of the India–Bangladesh Trade Agreement 1980, which states that "The two governments agree to make mutually beneficial arrangements for the use of their waterways, railways and roadways for commerce between the two countries and for passage of goods between two places in one country through the territory of the other". However, the proposal is still in the initial stages of negotiation.
The route has a major broad gauge railway line. Electrification of this double-track corridor is in progress with assistance from Central Organization for Railway Electrification (CORE). Additionally, the old metre gauge line (recently converted to a broad-gauge line) connects Siliguri Junction with Islampur in North Dinajpur District of West Bengal, via Bagdogra (the only airport of national interest in the corridor) and the bordering towns of Adhikari, Galgalia, Thakurganj, Naxalbari and Taiabpur with Nepal. National Highway 10 connects Siliguri to Guwahati in Assam, which is the most critical highway in the region, owing to insurgents operating in the vicinity.