(1) If personal injury is caused to a workman by accident arising out of and in the course of his employment, his employer shall be liable to pay compensation in accordance with the provisions of this Chapter: Provided that the employer shall not be so liable--
(b) in respect of any 4[ injury, not resulting in death, caused by] an accident which is directly attributable to--
(i) the workman having been at the time thereof under the influence of drink or drugs, or
(ii) the wilful disobedience of the workman to an order expressly given, or to a rule expressly framed, for the purpose of securing the safety of workmen, or
(iii) the wilful removal or disregard by the workman of any safety guard or other device which he knew to have been provided for the purpose of securing the safety of workmen. 5[ 5[