law: Representation of the People Act, 1950 
  21. Preparation and revision of electoral rolls 
  
  
  (1) The electoral roll
  
  for each constituency shall be prepared in the prescribed manner by reference
  
  to the qualifying date and shall come into force immediately upon its final
  
  publication in accordance with the rules made under this Act.
   64  [(2)] The said
  
  electoral roll:-
  (a) shall, unless otherwise directed by the
  
  Election Commission for reasons to be recorded in writing, be revised in the
  
  prescribed manner by reference to the qualifying date:-
  ( i ) before each
  
  general election to the House of the People or to the Legislative Assembly of a
  
  State; and
  (ii) before each bye-election to fill a casual
  
  vacancy in a seat allotted to the constituency; and
  (b) shall be revised in any year in the
  
  prescribed manner by reference to the qualifying date if such revision has been
  
  directed by the Election Commission:
  Provided  that if the electoral roll is not revised
  
  as aforesaid, the validity or continued operation of the said electoral roll
  
  shall not thereby be affected.]
  (3) Notwithstanding
  
  anything contained in sub-section (2), the Election Commission may at any time,
  
  for reasons to be recorded, direct a special revision of the electoral roll for
  
  any constituency or part of a constituency in such manner as it may think fit :
  Provided that subject to the
  
  other provisions of this Act, the electoral roll for the constituency, as in
  
  force at the time of the issue of any such direction, shall continue to be in
  
  force until the completion of the special revision so directed.