Population transfer in the Soviet Union was when people from different groups were forced to move from one place to another. It was used by the Soviet government in the 1940s and 1950s to end social and ethnic tensions between different groups. The Soviet government thought that if people lived in different places, they wouldn't have as much trouble getting along.
So, the government made some people move away so they could live in different places. The people who had to move were usually from Ukraine, Kazakhstan and other countries in the Soviet Union. The government also moved some ethnic minorities like Jews, Poles, and Germans away from their homes. Many people had to leave their homes and businesses behind. It was a really difficult time for them and their families.