The great 21st-century migration into cities will present both a great challenge for humanity and a significant opportunity for global economic growth. This paper describes the diverse patterns that define this metropolitan migration. It then lays out a framework for understanding the costs and...

We study a developing countries setting in which agglomeration efficiency of urban production attracts rural-to-urban migration, whereas urban pollution deters rural-to-urban migration. By means of a general equilibrium model we study the formation of policies aimed at striking a socially...