If the holder of a licence under section 4-
(a) has in or in connection with an application for a licence or renewal of a licence furnished the Director General with any information which to the knowledge of such holder is untrue or misleading in any material respect;
(b) has contravened or failed to comply with a condition subject to which the licence was issued;
(c) has contravened or failed to comply with a provision of this Act;
(d) has at any time been convicted of any offence which is of such a nature that in the opinion of the Director-general it renders him unsuitable or if such person is for any other reason in the opinion of the Director-General not a suitable person to carry on the activities authorized by the licence, or to be involved in such activities; or
(e) has ceased to carry on the activities authorized by the licence, the Director-General may by way of a notice in writing call upon him to show cause within the period specified in the notice, which period shall not be less than 20 days as from the date of the notice, why the licence in question should not be suspended or cancelled.