Certificates issued to the owners of bus lines may be suspended or revoked by the council only upon its finding that the owner is guilty of a material breach of the terms of the certificate of this chapter or of the resolution under which such certificate was authorized. Material breach shall be deemed to mean such a breach as in law would permit the non-breaching party to a contract to rescind a contract to which he is a party. (Ord. 73 NCS §9; prior code §24.52.)