Is the additional charge imposed on the importer for his delay in withdrawing the goods permissible (halal)? Is it permissible to consider it as compensation for damage incurred by the port? Is it permissible to increase the amount for the importer who withdraws his goods on time but delays payment?

It is permissible for the port to increase the ground rent on the importer if he delays in receiving his goods, due to the extended rental period and the loss of benefit from the land. The increase must be equivalent to the market rent or a known percentage. However, if the rent becomes a debt owed by the importer, it is not permissible to stipulate an increase on him, as that would be usury (riba).