Indian Stamp Act, 1899
(1) Except as otherwise expressly provided in this Act, all duties with which any instruments are chargeable shall be paid, and such payment shall be indicated on such instruments, by means of stamps — (a) according to the provisions herein contained; or (b) when no such provision is applicable thereto-as the [State Government] may be rule direct. (2) The rules made under sub-section (1) may, among other matters, regulate, — (a) in the case of each kind of instrument-the description of stamps which may be used; (b) in the case of instruments stamped with impressed stamps-the number of stamps which may be used; (c) in the case of bills of exchange or promissory notes *** the size of the paper on which they are written.