Urbanisation refers to increase in urban population.
Urbanisation is not a modern phenomenon. Infact it is a continous process which dates back to the indus valley civilisation, when cities and towns started coming up.
When people move from a rural place to an urban setting, they expect a certain standard of living. To meet these standards, many factories have to be set up and services need to be provided, which provides a boost for the economy.
But, on the other hand, rapid urbanisation, which has been taking place since the last few decades, takes a toll on the planet's health and the natural resources of the region. According to WHO, by 2050 more than 90 percent of the worlds population would be living in urban areas.
This would cause concentration of population in a few areas, thereby seriously affecting the environment.