Gst on rent petrol bunk

Section 12 (3) IGST Act : - 

place of supply of services directly in relation to an immovable property, including services provided by architects, interior decorators, surveyors, engineers and other related experts or estate agents, any service provided by way of grant of rights to use immovable property or for carrying out or co-ordination of construction work, shall be the location at which the immovable property is located or intended to be located.

Section 8(2) Of IGST Act, Subject to the provisions of section 12, supply of services where the location of the supplier and the place of supply of services are in the same State or same Union territory shall be treated as intra-State supply:

So Place of Supply in Your case is Karnataka and assuming you are also registered in the State of Karnataka, CGST & SGST will be charged on the Invoice being the services in relation to immovable property and Intra state supply of service.

However, if you (supplier) are registered outside Karnataka, then it will be Inter-supply and IGST will be charged.