Manipur, Tripura and Meghalaya attained statehood on January 21, 1972, under the North-Eastern Areas (Re-organisation) Act, over 24 years after India got independence. Manipur and Tripura were Union Territories before 1972, while Meghalaya was a part of Assam before becoming a full-fledged state. Sikkim became India's 22nd state on May 16, 1975, after the formation of the three states.