In January 1958, the PRC Hukou Registration Regulations (户口登记条例) were adopted. This divided the population into nongmin (农民, rural citizens), with an agricultural hukou, and shimin (市民, urban citizens), with a non-agricultural hukou, and grouped all citizens by locality. Millions of peasants had been recruited by the expanding state industrial enterprises in the urban areas as part of the first Five-Year Plan (1953-1957), and many more moved to the cities to look for urban jobs. To curb this rapid influx, the registration system aimed to restrict further rural-to-urban migration and to return rural migrants to the countryside. State welfare programs heavily favored urban residents; holders of agricultural hukous were unable to access these benefits and were saddled with inferior welfare policies. Transfer of hukou status was restricted. In 1964, greater limits were imposed on migration to big cities like Beijing and Shanghai. The hukou system was used as as a tool to control internal migration.