Pokhran-II was a series of five underground nuclear weapon tests conducted by India in the Thar Desert at the Pokhran Test Range in Rajasthan. Codenamed Operation Shakti, this event was an act of demonstrating India's nuclear capability and was the second such test series after the 1974 Smiling Buddha explosion. The tests were carried out on May 11 and May 13, 1998, under the government led by Prime Minister Atal Bihari Vajpayee.
The primary purpose of Pokhran-II was to establish a credible deterrent and address India's security concerns, which were heightened by the 1962 Sino-Indian War and China's 1964 nuclear test. The tests were a mechanism to publicly showcase the technological success of India's nuclear program and challenge the global "nuclear apartheid" that restricted non-signatories of the Nuclear Non-Proliferation Treaty (NPT). The operation involved five devices: a two-stage thermonuclear device (Shakti I), a fission device (Shakti II), and three sub-kiloton devices (Shakti III, IV, V). The tests achieved the scientific objective of giving India the capability to build fission and thermonuclear weapons with yields up to 200 kilotons (kt).
Pokhran-II connects directly to India's subsequent declaration as a Nuclear Weapon State and the formulation of its nuclear doctrine, which includes a No First Use (NFU) policy and the maintenance of a credible minimum deterrence. Internationally, the tests led to the enactment of United Nations Security Council Resolution 1172 and the imposition of economic sanctions by countries like the United States and Japan. The long-term impact includes the India-United States nuclear deal of 2005, which normalized India's civil nuclear energy program. The date May 11 is now commemorated as National Technology Day in India. The legacy of Pokhran-II is seen in the ongoing maturation of India's nuclear triad—land, air, and sea capabilities—to ensure an assured second-strike capability.