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. Coin series 1957–present (decimal) Naya paisa series 1957–1963 The antiquated spelling of "pice" was modified to "paisa" in the singular and "paise" in the plural. For public recognition, the new decimal paisa was termed 'Naya Paisa' (New Paisa) till 1 June 1964 when the term 'Naya' was dropped. The coins of 50p, 25p, 10p, 5p, 2p, and 1p had a legend in Devanagari script explaining the value of coin in terms of fraction of a rupee. Paisa series I with Devanagari Legend 1964 onwards In June 1964, the term 'Naya' was dropped and the coins were as fllowsreminted. The legend in Devanagari script explaining the value of coin in terms of fraction of a Rupee continued till it was finally dropped from the new design minted 1964 onwards. Series II without the Devanagari Legend (1964 - 1983) The coin minted from 1965 did not have the legend in Devanagari, explaining the value of the coin as a fraction of the rupee. Small-denomination coins which were formerly made of bronze, nickel-brass, cupro-nickel and aluminium-bronze were gradually minted in aluminium. The first coin minted in such type was the 3 paisa coin in 1964, which was a new denomination, and continued to be minted till 1971. One and Two paisa coins were changed to aluminium and were minted without the Devanagari legend from 1965. 20 paisa coin was introduced in 1968, which continued to be minted till 1971. Series III 1982 Onwards From 1982, New series was launched. the 20 paisa coin which was last minted in 1971, was reintroduced again, but in Aluminium. The size and the design of 10 paisa, 50 paisa and 1 rupee was changed, though they continued to be minted in the same metal. Coins of 3p, 2p and 1p were discontinued but continued to be the legal tender. Series IV 1988 Onwards In Series IV, 5 paisa