The Authority for advance ruling constituted under the provisions of a State Goods and Services Tax Act or Union Territory Goods and Services Tax Act shall be deemed to be the Authority for advance ruling in respect of that State or Union territory. However, the Government may, on the recommendation of the Council, notify any Authority located in another State / Union territory to act as the Authority for the State or the Union territory where Authority for Advance Ruling is not constituted.
(ICAI FAQ PUBLICATIONS 06-09-2017 Advance ruling under GST: faq no. 6)