5. (1) The Government may, by notification in the official Gazette, from time to time, vary, alter or adjust the base units of weights and measures and may, in relation to such units, specify such supplementary, derived, or other units or standard symbols or definitions as the General Conference on Weights and Measures or the International Organisation of Legal Metrology may recommend. Explanation.- For the purpose of this sub-section, “derived unit” shall mean a unit which is derived from the base or supplementary units or both. (2) The Government may specify such multiples and sub-multiples of, and physical constants and ratios of co-efficients in relation to such units of weight or measure as the General Conference on Weights and Measures or the International Organization of Legal Metrology may recommend. (3) The Government may, by notification in the official Gazette, declare, for such period as it may consider necessary, such special units of weight or measure as the General Conference on Weights and Measures or the International Organisation of Legal Metrology may recommend.