On October 16, 1964, China detonated its first atomic bomb at Lop Nur in the western desert. The test, the first by any state other than the United States, the Soviet Union, the United Kingdom, or France, was read in New Delhi as a sharp signal of the security environment India was about to face. India developed nuclear weapons in response to that signal — combined with the trauma of the 1962 Sino-Indian War, the growth of the Pakistani program, and a normative objection to the NPT’s division of states into nuclear “haves” and “have-nots” — and the path ran from the 1974 “peaceful nuclear explosion” to the 1998 Pokhran-II tests.
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The trigger was the Sino-Indian War of October–November 1962, in which Chinese forces delivered a sharp and humiliating defeat to the Indian military in the northeast. China’s first nuclear test, at Lop Nur on October 16, 1964, deepened the sense of vulnerability. By 1965, the Indian Atomic Energy Commission had formally discussed the possibility of a weapons program. The choice not to weaponize at that time, in favor of a “peaceful nuclear explosion” capability, was a political choice, not a technical one.
The Pokhran-I test of May 18, 1974 (codenamed Smiling Buddha) was officially described as a “peaceful nuclear explosion.” The device was a plutonium implosion design with a yield of 12 kilotons, similar to the Nagasaki bomb. The international response was the formation of the Nuclear Suppliers Group in 1975. India declared a moratorium on further tests in 1977; the moratorium was unilateral and held through the 1980s.
The Pokhran-II tests of May 11 and 13, 1998, conducted by the BJP government of Prime Minister Atal Bihari Vajpayee, included a thermonuclear device, several fission devices, and a sub-kiloton device. The official justification combined three arguments: that the security environment had deteriorated; that the NPT was inherently discriminatory; and that India required a credible minimum deterrent to maintain regional and global status.
The Indian nuclear doctrine — credible minimum deterrent and no first use — was articulated in a Draft Nuclear Doctrine published in August 1999 and adopted in modified form in January 2003. It is distinct from the 1988 Rajiv Gandhi Action Plan, a UN General Assembly proposal for global disarmament — the two are sometimes conflated in popular accounts.