Patents Act, 1970
59. Supplementary provisions as to amendment of application or specification
(1) No amendment of an application for a patent or a complete specification shall be made except by way of disclaimer, correction or explanation, and no amendment thereof shall be allowed, except for the purpose of correcting an obvious mistake, and no amendment of a complete specification shall be allowed the effect of which would be that the specification as amended would claim or describe matter not in substance disclosed in the specification before the amendment, or that any claim of the specification as amended would not fall wholly within the scope of a claim of the specification before the amendment.
(2) Where after the date of advertisement of acceptance of a complete specification, any amendment of the specification is allowed by the Controller or by the High Court,
(a) the amendment shall for all purposes be deemed to form part of the specification;
(b) the fact that the specification has been amended shall be advertised in the Official Gazette; and
(c) the right of the applicant or patentee to make amendment shall not be called in question except on the ground of fraud.
(3) In construing the specification as amended, reference may be made to the specification as originally accepted.