Transfer of ownership of goods in a bonded warehouse triggers IGST on the supply; customs duty remains payable at ex bond based on import value. Transfer or sale of imported goods while deposited in a customs bonded warehouse constitutes a supply taxable under IGST as an inter State supply, with value determined under CGST/IGST valuation rules; customs duties deferred at deposit remain payable on ex bonding based on the value determined at import under section 14, and post import costs are not added to the customs assessable value for ex bond duty computation.