April 8, 1973 (on March sixth Guichou), India to take over Sikkim administrative rights.

1973, the Indian government on the pretext of Sikkim domestic riots occurred, sending troops moved into Sikkim capital Gangtok. Then, on April 8, forced to take over all the powers of the Government of Sikkim, military occupation. April 10, 1975, Sikkim Assembly passed a resolution in India under the manipulation of deposed former King Namgyal, becomes an Indian state of Sikkim. (History TodayOnHistory.com) Indian Parliament passed a resolution Sikkim becomes a state in India to complete the steps of the annexation of Sikkim.