Place of Supply

No need to get registered at Delhi.

The company at Ranchi can direct its seller to deliver the goods to its purchaser at Delhi. In both the transactions IGST will be charged.

registration not required for delhi , when you purchase party collect IGST in basis of your registration at Ranchi, it is deemed to be interstate transaction and when you supply to delhi party you have to collect IGST in invoice. It is deemed to be interstate transaction as per IGST. I request to refer place of supply as per IGST to better understand.