The concessional rates
Section 115AC is a special regime for a narrow set of instruments: bonds of an Indian company or of a public-sector undertaking, and global depositary receipts of an Indian company, where a non-resident acquired them in foreign currency. For these, the ordinary slab and surcharge maths is replaced by flat rates.
Interest on the bonds and dividends on the GDRs are taxed at a flat 10%. Long-term capital gains on transferring them are taxed at a concessional rate too, 10% for transfers up to 22 July 2024, and 12.5% for transfers on or after 23 July 2024, following the wider capital-gains change, and computed without indexation. The trade-off is that no deduction is allowed for expenses against this income, and no Chapter VI-A deductions either, so it is a clean flat rate on the gross. For most holders the flat 10% on income is well below what the ordinary route would cost.
Often no return to file
A practical convenience comes with the regime. Under Section 115AC, if a non-resident's total Indian income consists only of interest or dividend income of this kind, and tax has been deducted at source on it, there is no obligation to file an Indian return of income.
So a non-resident whose only Indian income is interest on qualifying Indian company bonds, with the 10% deducted, is not forced into the return system. That said, if you have other Indian income, Indian rent, a property sale, other capital gains, the exemption from filing does not apply and you file as normal, putting this income in at its concessional rate. And if you want to claim a treaty rate lower than 10%, or a refund, you would file to do so. A practising CA checks whether you fall in the no-return category or should file to claim something back.