When did the state of Arunachal Pradesh come into existence under the State of Arunachal Pradesh Act, 1986?
The State of Arunachal Pradesh was formed under the State of Arunachal Pradesh Act, 1986. It came into existence on 15 April 1987. This information can be found in section 4(w.e.f. 15-4-1987) of the act.