law: Standards of Weights and Measures Act, 1976 
  5. Base unit of
  
  length. - 
  (1) The base
  
  unit of length shall be the meter.
  (2) The “meter” is the
  
  length equal to 1650 763.73 wave lengths in vacuum of the radiation
  
  corresponding to the transition between the levels 2p 10 and 5d5 of
  
  the krypton-86 atom.