Effective date of explanation: clarification that the inserted explanation applies from the original entry's commencement date. The explanation inserted under the statutory power to clarify notifications is effective from the inception of the original concessional-entry, so the exclusion of Government and Local Authority activities from the term 'business' applies from the original entry's commencement date. A deeming clause adopting a later issuance date does not affect the retrospective operation provided by the insertion mechanism. The circular is clarificatory in nature and implementation issues may be reported to the Commissioner.