There's been too much concentration of power in the hands of central authorities.中央政府手中集权过重。

This has also led to a concentration of wealth in a small number of hands.这也导致了财富集中在少数人手里。

The concentration of people in cities promotes economic growth.城市人口的集中促进经济增长。

The area has one of the world's greatest concentrations of wildlife.这个地区有世界最大的野生动物聚集地之一。