Section 3(3) in The President (Discharge of Functions) Act, 1969
(3)When the Vice-President,-(a)while acting as President, or(b)while discharging the functions of the President,is unable to discharge the functions of the President owing to absence, illness or any other cause, the Chief Justice of India or, in his absence, the seniormost Judge referred to in sub-section (1) shall discharge the said functions-(i)in the case referred to in clause (a), until a new President elected as aforesaid enters upon his office or until the Vice-President acting as President resumes his duties, whichever is earlier;(ii)in the case referred to in clause (b), until the President resumes his duties, or the Vice-President resumes his duties, whichever is earlier.
