Section 13(2) in The Indian Post Office Rules, 1933
(2)The right-hand of the address-side of a postcard is in all cases reserved for the address of the recipient, for the postage stamp or impression of stamping machine necessary for prepayment, which should, so far as possible, be affixed in the upper right-hand corner, and for the postal directions "Registered and "Acknowledgement due" but the left hand half of the address-side, as well as the back, may be used by the sender for the purpose of a written communication, or may be otherwise disposed of, subject to the restriction mentioned in clause (3) of this rule.Note I. A small space marked off by lines or minute dots to indicate the place where the postage stamp should be affixed is allowed on the upper right-hand corner of the address-side of postcards.
