The 'Map of India' series of definitive stamps was brought out at the time of the introduction of the decimal coinage system on the 1st April, 1957. Eleven stamps bearing the map of the country replaced all the stamps of the Five Year Plan series excepting the denominations of Re. 1/- and above. Subsequently in 1958 three more stamps in the denominations of 8 nP, 15 nP and 90 nP were added to this series. - Source: Information brochure by India post issued on 01.07.1966.