What the regime covers, and the rates
Chapter XII-A, Sections 115C to 115I, is a regime built for non-residents who invest in India with foreign money. It applies to foreign-exchange assets, meaning specified Indian assets, shares of an Indian company, deposits or debentures of Indian public companies, and central government securities, that a non-resident acquired in convertible foreign currency.
For these, investment income, the interest and dividends they throw off, is taxed at a flat 20%, and long-term capital gains on selling them are taxed at a reported 10%, computed without the benefit of indexation or the forex proviso. Because Indian capital-gains rates changed in 2024, the exact long-term figure is worth confirming for the year of sale, but the regime has historically taxed these gains at 10%, which can now be lower than the 12.5% that applies to many assets under the ordinary rules. That is the point of checking it: for some NRI holdings it genuinely undercuts the default.
Elective, with rollover and a continuation option
Two features make the regime more than just a rate. First, under Section 115F, if you reinvest the net proceeds of a long-term foreign-exchange asset into another specified asset or savings within six months, the gain is exempt proportionately, a rollover relief specific to this regime. Second, and unusually, under Section 115H you can choose to keep the concessional treatment on your existing foreign-exchange assets even after you return to India and become resident, by filing a declaration with your return, until those assets are sold or converted. So the lower rate does not automatically vanish the moment you move back.
The regime is elective. It is not forced on you, you can opt out for any assessment year and be taxed under the ordinary provisions if they work out better, which matters because the flat 20% on investment income can be worse than the slab for someone with little other income. So it is a genuine choice to weigh, not a default. A practising CA compares the special regime against the ordinary rates for your specific holdings and income, and files the declaration where continuing it after a return is worthwhile.