Urbanization: Urbanization is the process by which an increasing percentage of a population comes to live in urban areas rather than rural areas.
Megacity: A megacity is an urban area with a very large population, usually over 10 million people. These cities often face challenges related to infrastructure, transportation, and resource management.
Gentrification: Gentrification is the process of renovating deteriorated urban neighborhoods by means of the influx of more affluent residents. This can lead to displacement of lower-income residents and changes in the character of the neighborhood.