Wikipedia
Pokhran-II was the series of five nuclear bomb test explosions conducted by India at the Indian Army's Pokhran Test Range in May 1998. It was the second Indian nuclear test; the first test, code-named Smiling Buddha, was conducted in May 1974.
Pokhran-II consisted of five detonations, of which the first was a fusion bomb and the remaining four were fission bombs. These nuclear tests resulted in a variety of sanctions against India by a number of major states, including Japan and the United States.
On 11 May 1998, Operation Shakti (Pokhran-II) was initiated with the detonation of one fusion and two fission bombs; the word " Shakti" ( Devanagari: शक्ति) means "power" in Sanskrit. On 13 May 1998, two additional fission devices were detonated, and the Indian government led by Prime Minister Atal Bihari Vajpayee shortly convened a press conference to declare India a full-fledged nuclear state.
Many names are attributed to these tests; originally they were called Operation Shakti–98 (Power–98), and the five nuclear bombs were designated Shakti-I through Shakti-V. More recently, the operation as a whole has come to be known as Pokhran II, and the 1974 explosion as Pokhran-I.