The Nuclear Suppliers Group (NSG) is a multilateral export control regime and a voluntary association of 48 nuclear supplier countries. Its purpose is to prevent the proliferation of nuclear weapons by regulating the transfer of materials, equipment, and technology that could be used to develop them.
The NSG was formed in response to India's "Smiling Buddha" nuclear test in May 1974, which demonstrated that civilian nuclear technology could be diverted for military purposes. This event exposed the inadequacy of export controls under the existing Nuclear Non-Proliferation Treaty (NPT). The group, initially known as the London Club, held its first meeting in 1975.
The NSG works by implementing two sets of guidelines, published as INFCIRC/254 by the International Atomic Energy Agency (IAEA). Part I of the guidelines, published in 1978, lists items specifically designed for nuclear use, known as the "Trigger List," and requires comprehensive IAEA safeguards for importing non-nuclear-weapon states. Part II, added in 1992, governs the export of "dual-use" items that have both nuclear and non-nuclear applications. The NSG also follows a "no undercut policy" and adopted a "Non-Proliferation Principle" in 1994.
The NSG complements the NPT and works alongside the Zangger Committee. It is one of the four major Multilateral Export Control Regimes (MECR), which also include the Missile Technology Control Regime (MTCR), the Australia Group, and the Wassenaar Arrangement.
A major change relevant to India occurred in September 2008, when the NSG granted India a "clean waiver" from its rules. This waiver allowed NSG members to engage in civilian nuclear trade with India despite its status as a non-signatory to the NPT and its lack of full-scope IAEA safeguards. India formally applied for full membership in 2016, but its bid remains pending due to opposition from some members, notably China.