Arunachal Pradesh is an Indian state in Northeast India. It was formed from the erstwhile North-East Frontier Agency (NEFA) region, it became a Union territory on21 January 1972, and became a state on 20 February 1987. It borders the states of Assam and Nagaland to the south. It shares international borders with Bhutan in the west, Myanmar in the east, and a disputed border with China in the north at the McMahon Line. Itanagar is the state capital of Arunachal Pradesh. Arunachal Pradesh is the largest of the Seven Sister States of Northeast India by area. Arunachal Pradesh shares a 1,129 km border with China’s Tibet Autonomous Region. Its area is 83,743 km2 (32,333 sq mi) and population is 1,382,611.As of the 2011 Census of India, Arunachal Pradesh has a population of 1,382,611 and an area of 83,743 square kilometres (32,333 sq mi). It is an ethnically diverse state, with predominantly Monpa people in the west, Tani people in the center, Tai people in the east, and Naga people in the south of the state. About 45 tribes/sub-tribes live in the state. The main tribe of the state is Adi, Nyshi, Galo, Tagin, Apatani, and so forth. The Mishmi tribe has three sub-tribes, namely Idu-Mishmi, Digaru-Mishmi and Miju-Mishmi.A major part of the state is claimed by both the People’s Republic of China and Republic of China as part of the region of South Tibet. During the 1962 Sino-Indian War, most of Arunachal Pradesh was captured and temporarily controlled by the Chinese People’s Liberation Army.
In 1913-1914, representatives of the de facto independent state of Tibet and Britain met in India to define the borders of ‘Outer Tibet’ (with respect to China). British administrator Sir Henry McMahon drew the 550 miles (890 km) McMahon Line as the border between British India and Tibet, placing Tawang and other areas within British India. The Tibetan and British representatives devised the Simla Accord including the McMahon Line,but the Chinese representatives did not concur. The Simla Accord denies other benefits to China while it declines to assent to the Accord. The Chinese position was that Tibet was not independent from China and could not sign treaties, so the Accord was invalid, like the Anglo-Chinese (1906) and Anglo-Russian (1907) conventions. British records show that the condition for the Tibetan government to accept the new border was that China must accept the Simla Convention. As Britain was not able to get an acceptance from China, Tibetans considered the MacMahon line invalid. In the time that China did not exercise power in Tibet, the line had no serious challenges. In 1935, a Deputy Secretary in the Foreign Department, Olaf Caroe, “discovered” that the McMahon Line was not drawn on official maps. The Survey of India published a map showing the McMahon Line as the official boundary in 1937.In 1938, two decades after the Simla Conference, the British finally published the Simla Accord as a bilateral accord and the Survey of India published a detailed map showing the McMahon Line as a border of India. In 1944, Britain established administrations in the area, from Dirang Dzong in the west to Walong in the east.