What causes people to move from a rural area to an urban area?

There is no overarching single reason for the migration of
people to urban areas. In light of this, let me mentions a few
reasons. 

First, if we use China as a test case, we can say
that the mass migration of people from rural area to cities is based on governmental
incentives. As the central government decided to literally build cities overnight, they
needed workers. So, Chinese banks made loans to companies to build the infrastructure of
China. These jobs and hopes of a better life created a shift to urban
areas. 

Second, if we look at places like New York and
London, population increases took place because of the Industrial Revolution. People
followed jobs and opportunities. Therefore, people left rural areas to look for more
opportunities. 

Third, if we look at how rural areas are
hit hard by drought and other forces of nature that limit opportunities, then we can say
that part of the pull of cities is that there is little for people in rural
areas.

Finally, as cities grow, there is more to do, to
see, and to experience. Therefore, there is an allure, which cannot be underestimated.