As with all plastic polystyrene does not biodegrade. Instead it hangs around for years creating everlasting litter and problomatic pollution.
the boffs are working on the problem and here are their solutions
Polystyrene is difficult to recycle. Difficult but not impossible …
For those of you who insist on using plastic cups there is the save a cup recycling system
For the other stuff there is a process for recycling polystyrene that uses the styromelt system.
Polystyrene that ends up as litter has to be picked up – by the council – you pay the cost or by decent folk who care about the environmnet.