Tax on exempt supply by a restaurants under composition scheme

Yes need to pay GST. GST is payable 5% of the turnover in the State or Union territory. "Turnover in State" or "turnover in Union territory" means the aggregate value of all taxable supplies (excluding the value of inward supplies on which tax is payable by a person on reverse charge basis) and exempt supplies made within a State or Union territory by a taxable person, exports of goods or services or both and inter-State supplies of goods or services or both made from the State or Union territory by the said taxable person but excludes central tax, State tax, Union territory tax, integrated tax and
cess. [Section 2.(112)]
Since turnover definition includes exempted sales thus it is taxable