What is "chagai-i"

Chagai-I is the code name of five simultaneous underground nuclear tests conducted by Pakistan at 15:15 hrs PST on 28 May 1998. The tests were performed at Ras Koh Hills in the Chagai District of Balochistan Province.

Chagai-I was Pakistan's first public test of nuclear weapons. Its timing was a direct response to India's second nuclear tests, on 11 and 13 May 1998. These tests by Pakistan and India resulted in United Nations Security Council Resolution 1172 and economic sanctions on both states by a number of major powers, particularly the United States and Japan. By testing nuclear devices, Pakistan became the seventh nation to publicly test nuclear weapons. Pakistan's second nuclear test, Chagai-II, followed on 30 May 1998.