Whether the sale is an interstate sale or an intrastate sale, depends on two factors- 1. Location of the supplier 2. Place of Supply. As per section 12 of the IGST Act the Place of Supply for services by way of transportation of goods, including by mail or courier would be the location of the recipient if the recipient is a registered recipient but if the recipient is not a registered recipient, in that case, the place of supply will be the location where such goods are handed over for transportation. In your case, the place of supply will be Haryana since you are a registered recipient and the location of the supplier is Delhi which makes it an interstate sale. Therefore you are supposed to pay IGST on reverse charge basis.