Presumptive taxation of non-resident shipping income with return filing, assessment timelines, and port clearance controls Special provision governs computation of profits and gains from the shipping business, other than cruise shipping, carried on by non-residents. Income is deemed at 7.5% of qualifying freight and related receipts, no loss, allowance or deduction is permitted against the deemed income, and assets used in the business are depreciated on a deemed basis. The scheme also prescribes return filing by the master of the ship, assessment timelines, port clearance restrictions, and an option for regular assessment, with tax paid treated as advance tax for adjustment, refund or further payment as applicable.