<P> The Pokhran - II tests were a 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 instance of nuclear testing conducted by India; the first test, code - named Smiling Buddha, was conducted in May 1974 . </P> <P> Pokhran - II consisted of five detonations, the first of which was a fusion bomb while the remaining four were fission bombs . The tests were initiated on 11 May 1998, under the assigned code name Operation Shakti, with the detonation of one fusion and two fission bombs . 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 . The tests resulted in a variety of sanctions against India by a number of major states, including Japan and the United States . </P> <P> Many names have been assigned to these tests; originally these were collectively called Operation Shakti--98, and the five nuclear bombs were designated Shakti - I through to Shakti - V. More recently, the operation as a whole has come to be known as Pokhran II, and the 1974 explosion as Pokhran - I . </P> <P> Efforts towards building the nuclear bomb, infrastructure, and research on related technologies have been undertaken by India since World War II . Origins of India's nuclear program dates back to 1944 when nuclear physicist Homi Bhabha began persuading the Indian Congress towards the harnessing of nuclear energy--a year later he established the Tata Institute of Fundamental Research (TIFR). </P>

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