Until the outbreak of the Second World War, the main source of pollution continued to be the Potteries, although there was contamination from the Tame and other lower tributaries it was not as prominent. During the 1950s, however, the same problem of effluent dilution that occurred in Stoke began to become significant in Birmingham and the Black Country. Domestic effluent and polluting discharges from the metal working industries in the upper reaches, combined to affect the whole length of the tributary River Tame.