Gurgaon has many societies running 100% on DG supply, as getting DHBVN connection takes considerably long time. Our builder at the moment is charging us 18% GST on power supply that they provided from DG. I see electricity as an exempted commodity however builder insists they are required to charge GST on 100% electricity bill and any society not doing the same is doing so illegally. Can someone please advise if our builder is right in their approach?