law: Standards of Weights and Measures Act, 1976 
  12. Supplementary,
  
  derived, special and other units of weight or measure-Their symbols,
  
  definitions, etc.-
  (1) The Central
  
  Government may, by rules made in this behalf, specify, in relation to the base
  
  units of weight or measure, such supplementary, derived, or other units or
  
  standard symbols or definitions as the General Conference on Weights and
  
  Measures or the International Organization of Legal Metrology may recommend.
  
  Explanation. -”Derived unit” means a unit which is derived from the base
  
  or supplementary units, or both.
  (2) The Central
  
  Government may, by rules made in this behalf, specify, such multiples and
  
  sub-multiples of, and physical constants, and ratios or coefficients in
  
  relation to, units of weight or measure as the General Conference on Weights
  
  and Measures or the International Organization of Legal Metrology may
  
  recommend.
  (3) The Central
  
  Government may, by notification, 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 Organization of Legal
  
  Metrology may recommend.