Explanation:

The Chotanagpur region is the Adivasi dominated plateau in eastern India, which covers much of Jharkhand as well as adjacent parts of Odisha, West Bengal, Bihar and Chhattisgarh. Almost one hundred years before India’s First War of Independence (1857), the Adivasi tribals of the Chotanagpur plateau region had declared war against the British colonial rule in the area. The first ever revolt in India, against the exploitative landlords and the British government, happened in this region.

A landmark in the movement was the formation of the Chotanagpur Unnati Samaj in 1915, which acquired political overtones with the demand for a sub-state for the Adivasis. The demand was, however, turned down by the Simon commission.