GST REG

Sec. 22 of CGST Act, 2017 says  that registration is required in a state from where  the taxable supplies are made. In your case, AP is the place from where the construction services are provided so registration is required to be taken and charge CGST + SGST as both the location of supplier and place of supply will be in same state. Further, IGST credit on purchases made can be used to set off the CGST & SGST liability.