Specified Tax Rates per section 115E of Income Tax Act
where the total income of a NRI includes
(a) any income from investment or income from long-term capital gains of an asset other than a specified asset, the tax rate is 20%
(b) income by way of long-term capital gains, the rate of 10%
Definitions per section 115C of Income Tax Act
“investment income” means any income derived from a foreign exchange asset
“specified asset” means any of the following assets, namely :—
(i) shares in an Indian company;
(ii) debentures issued by an Indian company which is not a private company as defined in the Companies Act, 1956
(iii) deposits with an Indian company which is not a private company as defined in the Companies Act, 1956
(iv) any security of the Central Government as defined in clause (2) of section 2 of the Public Debt Act, 1944
(v) such other assets as the Central Government may specify in this behalf by notification in the Official Gazette.
“long-term capital gains” means income chargeable under the head “Capital gains” relating to a capital asset, being a foreign exchange asset which is not a short-term capital asset;
“foreign exchange asset” means any specified asset which the assessee has acquired or purchased with, or subscribed to in, convertible foreign exchange;
“convertible foreign exchange” means foreign exchange which is for the time being treated by the Reserve Bank of India as convertible foreign exchange for the purposes of the Foreign Exchange Management Act, 1999 (42 of 1999), and any rules made thereunder;
Also,, per section 115G. It shall not be necessary for a non-resident Indian to furnish under sub-section (1) of section 139 a return of his income if—
(a) his total income in respect of which he is assessable under this Act during the previous year consisted only of investment income or income by way of long-term capital gains or both; and
(b) the tax deductible at source under the provisions of Chapter XVII-B has been deducted from such income.
For more details refer: https://www.incometaxindia.gov.in/pages/i-am/non-resident.aspx