Standards of Weights and Measures Act, 1976
11. Base unit of amount of substance. -
(1) The base unit of amount of substance shall be the mole.
(2) The “mole” is the amount of substance of a system which contains as many elementary entities as there are atoms in 0.012 kilogram of carbon 12.
(3) When the mole is used, the elementary entities shall invariably be specified and may be atoms, molecules, ions, electrons, other particle, or specified groups of such particles.