The filthy, tattered notes you get from taxi drivers and vegetable vendors are unpleasant, but that's not the only thing wrong with paper money. It is easy to counterfeit-97 percent of fake banknotes are paper-and has a circulation life of about eight months at most. Worn notes also cause more errors in ATMs and high-speed note validators. The high cost of replacing high-circulating, low-denomination paper currency often takes the lion's share of any reserve bank's budget-Rs 100 million in the case of the Nepal Rastra Bank.

There's an alternative to the highly absorbent virgin cotton paper money. Polymer. This Dasain Nepal will be the 21st country to make the move to polymer, joining the ranks of Canada, Brazil, Romania, Thailand, Mexico, and China. In May this year, Note Printing Australia (NPA), a subsidiary of the Reserve Bank of Australia, won a tender worth $1.64 million to produce 50 million Rs 10 notes for the Rastra Bank. Nepal's first batch of Rs 10 polymer banknotes, which come into circulation this Dasain, closely resemble the original, retaining the black buck and the garuda images, and are the first legal tender with the image of King Gyanendra. The note features a security window with a vignette of the crown.

In 1966 a rash of counterfeiting in Australia led to research and development of a more secure currency. By 1996, Australia was the first country with a full series of circulating polymer banknotes. Polymer banknotes are expensive to make-they cost almost twice as much as paper-but their longer circulation life directly translates into huge savings for national banks. The Reserve Bank of New Zealand announced a saving of $7.2 million over three years in printing costs after switching to polymer banknotes.

The polymer substrate incorporates the polymer currency's trademark transparent windows. This is a security feature in itself, and design elements can be incorporated to make use of its unique properties. The creative Design Department at NPA say their designs are aimed at being aesthetically pleasing and also incorporating cutting edge verification technology that makes counterfeiting almost impossible. These features are immediately recognisable, making verification easier. (Trishna Gurung in Sydney)