overspill
/ˈəʊvəspɪl/noun
mass noun
1- the action or result of spilling over or spreading into another area溢洒; 溅出。
1.1
- Brit. people or things that spill over or are in excess, especially the surplus population moving or forced to move from an overcrowded to a less heavily populated area〈英〉溢出物; 过剩人口（尤指向人口较少地区迁移的过剩人口）。