Copyright Act, 1957
21. Right of author to relinquish copyright-
(1) The author of a work may relinquish all or any of the rights comprised in the copyright in the work by giving notice in the prescribed form to the Registrar of Copyrights and thereupon such rights shall, subject to the provision of sub section (3), cease to exist from the date of the notice.
(2) On receipt of a notice under sub section (1), the Registrar of Copyrights shall cause it to be published in the Official Gazette and in such other manner, as he may deem fit.
(3) The relinquishment of all or any of the rights comprised in the copyright in a work shall not affect any rights subsisting in favor of any person on the date of the notice referred to in sub section. (1).