IBM has found that many of the challenges the planet faces are concentrated in cities.

The model deemed it necessary to concentrate the Swedish population in cities, at the coast and in the south.

As Californians have concentrated in cities, they have come to care more about the country.

The party's voters are concentrated in larger cities, especially those with a university.

He also said the money should be concentrated in big cities, where it is needed most.

Instead, it has argued that the segregation results from complex social and economic forces that have concentrated poor people in cities.

Ecuador's diverse middle class is concentrated in cities and larger towns.

In addition, the remaining caseload is increasingly concentrated in large cities.

The elite jobs he describes are concentrated in expensive cities.

For the population to be concentrated in cities is certainly undesirable as regards quality of life.