Beijing's public toilets must not exceed two flies, according to new standards handed down by zealous officials striving to clean up China's notoriously filthy loos.

The unusual rule applies to lavatories in parks, railway stations, airports, hospitals, malls and supermarkets in the capital, said the News on Wednesday.

More conventional demands from the municipal committee in charge of the image of the city include an order that there is no accumulation of urine or water in the capital's public toilets and that bins aren't overflowing.

It is not clear if failing washrooms will be punished and if so how.

Beijing has launched several campaigns in the past to improve its numerous public toilets, especially before the .