12. Grounds for challenge.
(1) When a person is approached in connection with his possible appointment as an arbitrator, he shall disclose in writing any circumstances likely to give rise to justifiable doubts as to his independence or impartiality.
(2) An arbitrator, from the time of his appointment and throughout the arbitral proceedings, shall, without delay, disclose to the parties in writing any circumstances referred to in sub section (1) unless they have already been informed of them by him.
(3) An arbitrator may be challenged only if-
(a) circumstances exist that give rise to justifiable doubts as to his independence or impartiality, or
(b) he does not possess the qualifications agreed to by the parties.
(4) A party may challenge an arbitrator appointed by him, or in whose appointment he has participated, only for reason, of which he becomes aware after the appointment has been made.