Why is the sender required to pay for the return charges in order to get back the parcel returned from destination?

A parcel which cannot be delivered abroad is normally returned to the sender in due course (i.e., after expiry of the normal period of which it may be held at the disposal of the addressee in the destination) without prior notification, unless he has requested otherwise at the time of posting (such as abandoning the parcel). The sender of an undeliverable parcel which is returned through the most appropriate means in use by overseas postal administrations (either by air or surface route) is responsible for the return charges.

The return charges on an undeliverable parcel include postage, as in many cases charges levied abroad for warehousing and administrative cost and so on. Hence, the return charges from some overseas destinations may be higher than the original postage.