what is causing nuclear proliferation?
what is being done to prevent it?
Nuclear weapons are proliferating as a threat against one's enemies. During the Cold War, the Soviet Union and the U.S. were each afraid the other would use nuclear weapons on it, so each nation built up their own arsenal of weapons. Today, a few nations are still fearful of being the target of nuclear weapons, so some of them have developed their own as a threat to hostile nations.
Check this site.
http://www.world-nuclear.org/info/inf12.html