Presumptive taxation for cruise ship operations by non-residents applies with specific eligibility, computation, and deduction restrictions. Special presumptive taxation applies to a non-resident engaged in the business of operation of cruise ships, with profits and gains chargeable under the head 'Profits and gains of business or profession' computed at 20% of the aggregate of amounts paid or payable and received or deemed received on account of carriage of passengers. The regime is subject to prescribed operational conditions, disallows deductions, and deems depreciation for written down value computation. It also refers to a lease rentals exemption for foreign companies leasing cruise ships to specified companies within the stated group relationship and period.