Provisional refund restrictions: Registered persons without Aadhaar authentication or supplying specified goods barred from provisional refunds. Notification under section 54(6) excludes from provisional refund any registered person who has not completed Aadhaar authentication under the state GST rule, and suppliers of specified goods-areca nuts, pan masala, tobacco and manufactured tobacco substitutes, and essential oils-identified by Customs Tariff classifications, applying the interpretive rules of the First Schedule to the Customs Tariff Act to determine coverage.