Definition - What does Megacity mean?
A megacity is an urban area with a population of more than 10 million people. The massive city is a recent historical phenomenon, with the world's first megacity, New York, reaching the ten million population in 1930. There are now 34 megacities in the world, many of which are locacted in the developing countries of Asia, Africa and Latin America.
Safeopedia explains Megacity
The world's largest city is Tokyo-Yokohama, with around 38 million people. Only three of the top ten megacities in the world are in high income countries (Tokyo-Yokohama, New York and Seoul-Inchon). Three more are in middle-income China, with the remaining four in low income countries. The push towards urbanization is forecast to continue, with the United Nations forecasting an increase of 1.1 billion in the next 15 years.