Megacity means: A metropolitan or city with an extremely high average density and/or population. Megacity can be defined as an urban agglomeration that has a population greater than 10 million. However, the United Nations considers it a metropolitan area with at least 5,000,000 people and a consistent urban density. The majority of megacities in the world are located in developing countries, particularly in sub-Saharan Africa, South and East Asia, which are rapidly becoming more urbanized than the United States and Latin America. These cities, however, are built without any regulation of their construction or infrastructure. It is expected that 60 percent of the global population will live in cities by 2030. (in Community Dictionary, added by Miah Harrison)