India still not part of NSG, formed after 1974 nuke test
Nuclear Suppliers Group was founded after India conducted its first nuclear test on May 18, 1974. NSG's website says the explosion by a non-nuclear-weapon state "demonstrated that nuclear technology transferred for peaceful purposes could be misused." The 48-nation group which controls trade of nuclear material has blocked India's membership citing it is non-signatory to Non-Proliferation Treaty.