人口减少
Depopulation \De*pop`u*la"tion\, n. [L. depopulatio pillaging:
cf. F. d['e]population depopulation.]
The act of depopulating, or condition of being depopulated;
destruction or explusion of inhabitants.
The desolation and depopulation [of St.Quentin] were
now complete. --Motley.
depopulation
n : the condition of having reduced numbers of inhabitants (or
no inhabitants at all)