law: 34. Mode of executing contracts on behalf of Board.-
  (1) Every contract shall, on behalf of a Board, be made by the Chairman 3[or by any such officer of the Board not below the rank of the Head of a department as the Chairman may, by general or special order, authorise in this behalf] and shall be sealed with the common seal of the Board:
  Provided that no contract whereof the value or amount exceeds such value or amount as the Central Government may from time to time fix in this behalf shall be made unless it has been previously approved by the Board:
  Provided further that no contract for the acquisition or sale of immovable property or for the lease of any such property for a term exceeding thirty years, and no other contract whereof the value or amount exceeds such value or amount as the Central Government may from time to time fix in this behalf, shall be made unless it has been previously approved by the Central Government.
  (2) Subject to the provisions of sub-section (1), the form and manner in which any contract shall be made under this Act shall be such as may be prescribed by regulations made in this behalf.
  (3) No contract which is not made in accordance with the provisions of this Act and the regulations made thereunder shall be binding on the Board.