As per Section 12(3) of the CGST Act, 2017 in case of supplies of goods in respect of which tax is paid or liable to be paid on reverse charge basis, the time of supply shall be the earliest of the following dates, namely :-
Provided that where it is not possible to determine the time of supply under clause (a) or clause (b) or clause (c), the time of supply shall be the date of entry in the books of account of the recipient of supply.
As per Section 13(3) of the CGST Act, 2017 in case of supplies for Services in respect of which tax is paid or liable to be paid on reverse charge basis, the time of supply shall be the earliest of the following dates, namely:-
Provided, where it is not possible to determine time of supply by using above methods under clause (a) and clause (b), the time of supply shall be the date of entry in the books of account of the recipient of supply.