law: Water (Prevention and Control of Pollution) Act, 1974
  18. Power to give Direction.
  
  In the performance of its functions under this
  
  Act -
  (1) (a) the Central Board shall be bound by
  
  such directions in writing as the Central Government may give to it; and
  (b) every State Board
  
  shall be bound by such directions in writing as the Central Board or the State
  
  Government may give to it :
  Provided that where a direction
  
  given by the State Government is inconsistent with the direction given by the
  
  Central Board, the matter shall be referred to the Central Government for its
  
  decision.
  (2) Where the Central Government is of the
  
  opinion that any State Board has defaulted in complying with any directions
  
  given by the Central Board under sub-section (1) and as a result of such
  
  default a grave emergency has arisen and it is necessary or expedient so to do
  
  in the public interest, it may, by order, direct the Central Board to perform
  
  any of the functions of the State Board in relation to such area, for such
  
  period and for such purposes, as may be specified in the order.
  (3) Where the Central Board performs any of
  
  the functions of the State Board in pursuance of a direction under sub-section
  
  (2), the expenses, if any, incurred by the Central Board with respect to the
  
  performance of such functions may, if the State Board is empowered to recover
  
  such expenses, be recovered by the Central Board with interest (at such
  
  reasonable rate as the Central Government may, by order, fix) from the date
  
  when a demand for such expenses is made until it is paid from the person or
  
  persons concerned as arrears of land revenue or of public demand.
  (4) For the removal of doubts, it is hereby
  
  declared that any directions to perform the functions of any State Board given
  
  under sub-section (2) in respect of any area would not preclude the State Board
  
  from performing such functions in any other area in the State or any or its
  
  other functions in that area.