The National Security Act, 1980 (NSA) is an Act of the Indian Parliament, specifically a preventive detention law, enacted to provide for detention in certain cases and for matters connected therewith. It was promulgated on September 23, 1980, and assented to on December 27, 1980, during the Indira Gandhi Government. The Act, which extends to the whole of India, was created to replace the repealed Maintenance of Internal Security Act (MISA) of 1971, filling the gap in preventive detention legislation that had existed since MISA's repeal in 1977.
The NSA works by empowering the Central and State Governments to issue a detention order under Section 3 to prevent a person from acting in any manner prejudicial to the security of India, the maintenance of public order, or the maintenance of supplies and services essential to the community. The maximum period of detention permitted under the Act is 12 months. A detention order can also be made by a District Magistrate or Commissioner of Police, but it must be approved by the State Government within 12 days. The Act connects directly to the constitutional provision for preventive detention under Article 22(3)(b). Historically, it is the successor to the Preventive Detention Act of 1950 and MISA. Unlike punitive laws such as the Unlawful Activities (Prevention) Act (UAPA), the NSA focuses on preventing potential threats before a crime is committed. The Act, which contains 18 sections, remains in force and has not been recently replaced or significantly amended.