Space traveller returns to earth

[Jesaka]

Library book read in 1970. While space traveller away earth divided in two areas. The side he’s landed on is highly controlled. Only the super intelligent work. Everything is automated. Water is drugged so everyone content. Throw away society. Those who can’t live under these conditions are banished to the other side. No idea what the title or author’s name is.

 

[Danny McG]

Can you remember anything about the other side he is banished to?