This is a street corner in Whistler street in Manly. Cigarette butts containing plastic filters are the most littered item in the world. Many smokers assume the filters are made of a biodegradable material. In fact, filters are made of cellulose acetate -- a type of plastic that can take up to a decade to decompose. About 6 trillion cigarettes are manufactured a year and over 90% of them contain plastic filters. That's more than one million tonnes of plastic. Tossing a cigarette butt on the ground is one of the most accepted forms of littering, according to the World Health Organization. About two-thirds of butts are dumped irresponsibly -- stubbed out on pavements or dropped into gutters, from where they are carried via storm drains to streams, rivers and oceans. A recent study placed fish in water in which cigarette butts had been soaked and removed. After four days, half the fish had died, showing that cigarette butts "seep in into the aquatic environment and are toxic and deadly to living creatures.