When a SEZ supplies goods or services or both to any one, it will be considered to be a regular inter-state supply and will attract IGST. The exception to this is, when a SEZ supplies goods or services or both to a Domestic Tariff Area (DTA), this will be considered as an export to DTA (Which is exempt for the SEZ) and customs duties and other Import duties will be payable by the person receiving these supplies in DTA.