<Tr> <Td> Half Anna </Td> <Td> </Td> <Td> </Td> <Td> Square </Td> <Td> 19.5 mm </Td> <Td> 1950 - 1955 </Td> </Tr> <Tr> <Td> One Pice </Td> <Td> </Td> <Td> </Td> <Td> Bronze </Td> <Td> Circular </Td> <Td> 21 mm </Td> <Td> 1950 - 1955 </Td> </Tr> <P> The move towards decimalization was afoot for over a century . However, it was in September, 1955 that the Indian Coinage Act was amended for the country to adopt a metric system for coinage . The Act came into force with effect from 1 April 1957, after which anna and pice denominations were demonetised . The rupee remained unchanged in value and nomenclature . It, however, was now divided into 100' paisa' instead of 16 annas or 64 pice . Effective from 30 June 2011, all coins in denominations of 25 paisa and below were officially demonetized . </P> <Table> <Tr> <Th> Pre-decimal currency (1950 - 1957; minting ceased in 1955) </Th> <Th> Decimal currency replacement (1957--present) </Th> <Th> Decimal currency (dates minted) </Th> </Tr> <Tr> <Td> N / A </Td> <Td> 10 rupees </Td> <Td> 2006--present </Td> </Tr> <Tr> <Td> N / A </Td> <Td> 5 rupees </Td> <Td> 1992--present </Td> </Tr> <Tr> <Td> N / A </Td> <Td> 2 rupees </Td> <Td> 1982--present </Td> </Tr> <Tr> <Td> Rupee </Td> <Td> Rupee (divided into 100 new paisa 1957 - 1964; divided into 100 paisa 1964--present . </Td> <Td> 1962--present </Td> </Tr> <Tr> <Td> Half rupee </Td> <Td> 50 paisa </Td> <Td> 1960--present </Td> </Tr> <Tr> <Td> Quarter rupee </Td> <Td> 25 paisa </Td> <Td> 1957 - 2002 . Demonetized from 2011 . </Td> </Tr> <Tr> <Td> N / A </Td> <Td> 20 paisa </Td> <Td> 1968 - 1994 . Demonetized from 2011 . </Td> </Tr> <Tr> <Td> 2 annas </Td> <Td> 10 paisa </Td> <Td> 1957 - 1998 . Demonetized from 2011 . </Td> </Tr> <Tr> <Td> Anna </Td> <Td> 5 paisa </Td> <Td> 1957 - 1994 . Demonetized from 2011 . </Td> </Tr> <Tr> <Td> N / A </Td> <Td> 3 paisa </Td> <Td> 1964 - 1972; proofs minted until 1981 . Demonetized from 2011 . </Td> </Tr> <Tr> <Td> Half anna </Td> <Td> 2 paisa </Td> <Td> 1957 - 1979; proofs minted until 1981 . Demonetized from 2011 . </Td> </Tr> <Tr> <Td> Pice </Td> <Td> Paisa </Td> <Td> 1957 - 1972; proofs minted until 1981 . Demonetized from 2011, but retained as a unit of currency . </Td> </Tr> </Table>

When was the decimal system of currency introduced in india