India conducts a series of nuclear tests from 11 to 13 May 1998

The UN Security Council in Summer 1998. Image: UN Photo/Evan Schneider

11 to 13 May 1998 - Pokhran Tests

From 11 to 13 May 1998, India conducted a series of nuclear explosions which it openly declared as nuclear weapon tests. It had termed its previous nuclear explosion in 1974 as “peaceful” – naming it “Smiling Buddha” accordingly.

The 1998 test series consisted of a number of underground explosions at the Pokhran test site. According to India, one of these tests was the successful detonation of a thermonuclear weapon – a claim challenged by outside scientists on the basis of the relatively low yield measured by seismic stations (the first stations of the CTBTO's International Monitoring System were still under construction at the time).

Nehru was the first to advocate a nuclear test ban.

However, prior to the 1974 and 1998 nuclear tests, India had spearheaded the movement to ban nuclear testing. In 1954, Indian Prime Minister Jawaharlal Nehru proposed a nuclear “standstill” agreement. A first milestone for nuclear arms control was reached with the 1963 Partial Test Ban Treaty, which limited nuclear testing to the underground.

Only the 1996 CTBT, which opened for signature in 1996, bans all forms of nuclear testing. Of the 44 countries that have to ratify the Treaty for its entry into force, 36 have already done so. Of the eight remaining, China, Egypt, Iran, Israel and the United States have already signed.

India and Pakistan, together with the Democratic People’s Republic of Korea, have yet to both sign and ratify the CTBT. These three are the only countries to have conducted nuclear tests and broken the de-facto moratorium in place since the CTBT's opening for signature.

Read more on the 1998 South Asian nuclear tests.