noun
overconcentration; excessive concentration in one place
Often used in socio-economic contexts, especially referring to the concentration of population, political power, and cultural institutions in Tokyo. Can also apply to other forms of heavy centralization.
東京への一極集中が問題になっている。
The overconcentration in Tokyo has become a problem.
一極集中を
Decentralization is being promoted to correct the overconcentration.