Section 4 in The Coinage Act, 2011
Title: Denominations, dimensions, designs and composition of coins
Coins may be minted at the Mints or at any other place authorised under the proviso to section 3 of such denominations not higher than one thousand rupees and of such dimensions and designs and containing such metals or mixed metals of such composition or any other material as may be prescribed by the Government.
Title: Standard weight and remedy
The standard weight of the coin of any denomination, minted under the provisions of section 4, and the remedy allowed in making of such coins, shall be such as may be prescribed in this behalf by the Government from time to time.
Title: Coin when a legal tender
(1) The coins issued under the authority of section 4 shall be a legal tender in payment or on account, in case of—
(a) a coin of any denomination not lower than one rupee, for any sum not exceeding one thousand rupees;
(b) a half-rupee coin, for any sum not exceeding ten rupees;
(c) any other coin, for any sum not exceeding one rupee:
Provided that the coin has not been defaced and has not lost weight so as to be less than such weight as may be prescribed in its case.
(2) All new coins in the naya paisa series, designated as such under the notification of the Government of India in the Ministry of Finance, Department of Economic Affairs, Number S.R.O. 1120, dated the 11th May, 1956 issued prior to the commencement of the Indian Coinage (Amendment) Act, 1964 (17 of 1964), shall continue to be a legal tender in payment or on account, in case of,--
(a) a half-rupee or fifty naye paise coin, for any sum not exceeding ten rupees;
(b) any other coin, for any sum not exceeding one rupee.
Title: Decimal system of coinage
(1) The rupee shall be divided into one hundred units and any such unit may be designated by the Government, by notification, under such name as it thinks fit.
(2) All references in any enactment or in any notification, rule or order under any enactment or in any contract, deed or other instrument to any value expressed in annas, paisa and pies shall be construed as references to that value expressed in units referred to in sub-section (1) converted thereto at the rate of sixteen anna, sixty-four paise or one hundred and ninety-two pies to one hundred units referred to in subsection (1).
(3) All references in any enactment or in any notification, rule or order under any enactment or in any contract, deed or other instrument to any value in naya paisa or naye paise shall be construed as references to that value expressed respectively in units referred to in sub-section (1).
Title: Power to call in coin
Notwithstanding anything contained in section 6, the Government may, by notification, call in with effect from such date as may be specified in the notification, any coin, of whatever date or denomination and on and from the date so specified, such coin shall cease to be a legal tender, save to such extent as may be specified in the notification.