law: Patents Act, 1970
  31. Anticipation by public display, etc. 
  An invention claimed in a complete specification shall not be
  
  deemed to have been anticipated by reason only of-
  (a) the display of the invention with the consent of the true
  
  and first inventor or a person deriving title from him at an industrial or
  
  other exhibition to which the provisions of this section have been extended by
  
  the Central Government by notification, in the Official Gazette, or the use
  
  thereof with his consent for the purpose of such an exhibition in the place
  
  where it is held; or
  (b) the publication of any description of the invention in
  
  consequence of the display or use of the invention at any such exhibition as
  
  aforesaid; or
  (c) the use of the invention, after it has been displayed or
  
  used at any such exhibition as aforesaid and during the period of the
  
  exhibition, by any person without the consent of the true and first inventor or
  
  a person deriving title from him; or
  (d) the description of the invention in a paper read by the true
  
  and first inventor before a learned society or published with his consent in
  
  the transactions of such a society, if the application for the patent is made
  
  by the true and first inventor or a person deriving title from him not later
  
  than six months after the opening of the exhibition or the reading or
  
  publication of the paper as the case may be.