Q.Distinguish between CGST, SGST and IGST. When is each levied?

CGST and SGST are charged together on an intra-state supply, while IGST is charged alone on an inter-state supply — the difference is about which government collects the tax and on which kind of transaction.

CGST (Central Goods and Services Tax). Levied by the Central Government on an intra-state supply of goods or services — that is, a supply where the seller and the buyer are located in the same state. It is charged alongside SGST, not instead of it, on the same transaction value.

SGST (State Goods and Services Tax). Levied by the State Government of the state in which an intra-state supply takes place, again on the same transaction value as CGST, and usually at the same rate as CGST, so the two together make up the applicable GST rate (e.g., 9% + 9% for an 18% rate).

IGST (Integrated Goods and Services Tax). Levied by the Central Government alone on an inter-state supply — where the seller and buyer are in different states — or on an import of goods/services into India. Rather than splitting the tax into a central and a state component on the invoice, a single IGST is charged at a rate equal to what CGST + SGST combined would have been for that good or service. The Centre subsequently apportions the state component of this collection to the state where the goods or services are ultimately consumed, consistent with GST's destination-based design.

The underlying distinction. The real difference is not the rate (CGST+SGST together and IGST are meant to work out to the same total tax burden) but which government(s) collect the tax and how, based purely on whether the buyer and seller are in the same state or different states. This structure allows both the Centre and the states to retain their constitutional share of indirect tax revenue under one unified GST law, instead of the older system where the Centre and states levied entirely separate taxes (excise duty, service tax versus VAT, central sales tax) with no built-in mechanism to share the same base.