The NPT placed two non-proliferation requirements on the NNWS. Article II expects the NNWS not to indulge in any activity related to nuclear weapons or other nuclear explosive devices. Article III(1) requires the NNWS to accept nuclear safeguards to be implemented by IAEA. Recently, the IAEA has proposed State-Level Concept (SLC) for verifying the presence or absence of undeclared nuclear material and activities in the state within the provisions of the CSA.