GST is levied on all transactions such as sale, transfer, purchase, barter, lease, or import of goods and/or services. India will adopt a dual GST model, meaning that taxation is administered by both the Union and State Governments. Transactions made within a single state will be levied with Central GST (CGST) by the Central Government and State GST (SGST) by the government of that state. For inter-state transactions and imported goods or services, an Integrated GST (IGST) is levied by the Central Government.
GST CUTTACK Accounting System

GST is a consumption based tax, therefore, taxes are paid to the state which the goods or services are consumed not the state in which they were produced. IGST complicates tax collection for State Governments by disabling them to collect the tax owed to them directly from the Central Government. Under the previous system, a state would have to only deal with a single government in order to collect tax revenue