law: Companies Act, 2013 
  163.
  
    Option
  
  to adopt principle of proportional representation for appointment of directors.
  Notwithstanding
  
  anything contained in this Act, the articles of a company may provide for the
  
  appointment of not less than two-thirds of the total number of the directors of
  
  a company in accordance with the principle of proportional representation,
  
  whether by the single transferable vote or by a system of cumulative voting or
  
  otherwise and such appointments may be made once in every three years and
  
  casual vacancies of such directors shall be filled as provided in sub-section (4 )
  
  of section 161.