(4) The Central Government may, from time to time, issue directions to licensees generally or to any licensee in particular for the purpose of regulating the exhibition of any film or class of films, so that scientific films, films intended for educational purposes, films dealing with news and current events, documentary films or indigenous films secure an adequate opportunity of being exhibited, and where any such directions have been issued those directions shall be deemed to be additional conditions and restrictions subject to which the licence has been granted.