Section 3(1) in The President (Discharge of Functions) Act, 1969
(1)In the event of the occurrence of vacancies in the offices of both the President and the Vice-President, by reason in each case of death, resignation or removal, or otherwise, the Chief Justice of India or, in his absence, the seniormost Judge of the Supreme Court of India available shall discharge the functions of the President until a new President elected in accordance with the provisions of the Constitution to fill the vacancy in the office of the President enters upon his office or a new Vice-President so elected begins to act as President under article 65 of the Constitution, whichever is earlier.
