21. (1) Before issuing a licence to make or manufacture any weight or measure to which this Chapter applies, the Government or any person authorised by it in this behalf shall satisfy itself or himself, as the case may be, that a certificate of approval of the model of such weight or measure has been granted under section 20. (2) Where any certificate of approval of any model has been revoked by the authorised person, the licence issued for making or manufacturing of any weight or measure in accordance with such model shall stand suspended: Provided that such suspension shall stand vacated if such model is subsequently approved by the authorised person.