(short for "Zero Population Growth") is a 1972 Danish-American dystopian science fiction film directed by Michael Campus and starring Oliver Reed and Geraldine Chaplin.

Because of the permanent thick smog that has settled over the dismal cities that now cover the Earth's entire surface, all animals – even common household pets - are extinct.

Russ (Oliver Reed) and Carol McNeil (Geraldine Chaplin) work in a museum recreating life in the 20th century.

Once Carol decides to break the law and have a baby, they must not only avoid the prying eyes of the Big Brother-like government but also the growing jealousy of their own friends.

Finally, the McNeils are captured and placed under one of the state's execution domes, but the couple, along with the baby, manage to escape by digging underground, making their way through darkened tunnels in a raft to a remote island where there is no visible pollution.

Further growth of the population is unthinkable, and the leaders finally settle on the only possible solution, which is soon announced by the World Government satellite: "All citizens stand by.

There will be constant surveillance by StatePol and a large reward in extra calories for any citizen who reports the presence of an outlaw child.

"To give the world some semblance of normality, realistic mechanical babies are devised to pacify the maternal instincts of 10 billion women.