Exclusion of government activities from 'business' clarifies GST applicability; central, state and local authorities acting as public authorities excluded. The notification inserts an explanation narrowing the term 'business' in a State tax rate item: for that item, 'business' does not include any activity or transaction undertaken by the Central Government, a State Government or any local authority when they act as public authorities, thereby clarifying the scope and applicability of the earlier notification.