Definition of business excludes government public authority activities, clarifying GST rate notification applicability for taxation treatment. Inserts an Explanation to Notification No.11/2017-State Tax (Rate) stating that, for item (vi) against serial number 3, the term 'business' shall not include any activity or transaction undertaken by the Central Government, a State Government or any local authority when they are engaged as public authorities. The clarification narrows the taxable scope of that item and is deemed to have come into force on 27th July, 2018.