Background
Arms control advocates had campaigned for the adoption of a treaty banning all nuclear explosions since the early 1950s, when public concern was aroused as a result of radioactive fall-out from atmospheric nuclear tests and the escalating arms race.

Over 50 nuclear explosions were registered between 16 July 1945, when the first nuclear explosive test was conducted by the United States at Alamogordo, New Mexico, and 31 December 1953.

Prime Minister Nehru of India voiced the heightened international concern in 1954, when he proposed the elimination of all nuclear test explosions worldwide.

However, within the context of the cold war, scepticism in the capability to verify compliance with a comprehensive nuclear-test ban-treaty posed a major obstacle to any agreement.

Partial Test Ban Treaty, 1963
Limited success was achieved with the signing of the Partial Test Ban Treaty in 1963, which banned nuclear tests in the atmosphere, underwater and in space. However, neither France nor China, both nuclear weapon States, signed the PTBT.

Non-proliferation Treaty, 1968
A major step towards the non-proliferation of nuclear weapons came with the signing of the Nuclear Non-proliferation Treaty (NPT) in 1968. Under the NPT, non-nuclear weapon States were prohibited from, inter alia, possessing, manufacturing or acquiring nuclear weapons or other nuclear explosive devices. All signatories were committed to the goal of nuclear disarmament.

Negotiations for the CTBT
Given the political situation prevailing in the subsequent decades, little progress was made in nuclear disarmament until 1991. Parties to the PTBT held an amendment conference that year to discuss a proposal to convert the Treaty into an instrument banning all nuclear-weapon tests; with strong support from the UN General Assembly, negotiations for a comprehensive test-ban treaty began in 1993.

Adoption of the CTBT, 1996
Intensive efforts were made over the next three years to draft the Treaty text and its two annexes, culminating in the adoption of the Comprehensive Nuclear-Test-Ban Treaty (CTBT) on 10 September 1996 by the United Nations General Assembly in New York.

The CTBT, which prohibits all nuclear test explosions, was opened for signature in New York on 24 September 1996, when it was signed by 71 States, including the five nuclear-weapon States.

World leaders signing the Comprehensive Nuclear-Test-Ban Treaty (left to right): United States of America, China, France, Russian Federation and United Kingdom.