A nuclear-weapons-free zone, or NWFZ is defined by the United Nations as an agreement which a group of states has freely established by treaty or convention, that bans the use, development, or deployment of nuclear weapons in a given area, that has mechanisms of verification and control to enforce its obligations, and that is recognized as such by the General Assembly of the United Nations.
This would be a major step forward in eliminating the problem of nuclear proliferation and the threat of nuclear war. Iran has already tentatively agreed to this proposal.