Patents Act, 1970
141. Determination of certain contracts
(1) Any contract for the sale or lease of a patented article or for license to manufacture, use or work a patented article or process, or relating to any such sale, lease or license, whether made before or after the commencement to this Act, may at any time after the patent or all the patents by which the article or process was protected at the time of the making of the contract has or have ceased to be in force, and notwithstanding anything to the contrary in the contract or in any other contract, be determined by the purchaser, lessee, or licensee, as the case may be, of the patent on giving three months' notice in writing to the other party.
(2) The provisions of this section shall be without prejudice to any right of determining a contract exercisable apart from this section.