In case of inter-State transactions, the Centre would levy and collect the Integrated Goods and Services Tax (IGST) on all inter-State supplies of goods and services under Article 269A (1) of the Constitution. The IGST would roughly be equal to CGST plus SGST. The IGST mechanism has been designed to ensure seamless flow of input tax credit from one State to another. The inter-State seller would pay IGST on the sale of his goods to the Central Government after adjusting credit of IGST, CGST and SGST on his purchases (in that order). The exporting State will transfer to the Centre the credit of SGST used in payment of IGST. The importing dealer will claim credit of IGST while discharging his output tax liability (both CGST and SGST) in his own State. The Centre will transfer to the importing State the credit of IGST used in payment of SGST.Since GST is a destination-based tax, all SGST on the final product will ordinarily accrue to the consuming State.
A diagrammatic representation of the working of the IGST model for inter-State transactions is shown in Figure 2 below.