The Treaty on the Non-Proliferation of Nuclear Weapons (NPT), adopted in 1968, is the major international agreement aimed at preventing the spread of nuclear weapons and promoting peaceful uses of nuclear energy. The treaty categorized countries into nuclear-weapon states (those that tested nuclear weapons before the treaty) and non-nuclear-weapon states. It commits the nuclear-armed states to pursue disarmament and encourages non-nuclear states to forego developing their own nuclear arsenals. As of now, it is considered a cornerstone of global efforts to control nuclear proliferation and foster international peace and security, with nearly 190 signatory countries.