66. The Minister may revise, suspend or cancel a permit or a certificate issued by him where the holder
(1) does not meet or no longer meets the requirements prescribed in this Act and the regulations thereunder for obtention or renewal of the permit or certificate;
(2) fails to comply with the requirements, obligations and restrictions that apply to the carrying out or performance of his activities;
(3) has failed or refused to submit to the examination required under section 61;
(4) has ceased his activities.