The number of urban areas with more than 10 million inhabitants — sometimes called “megacities” — has nearly tripled in the last 24 years, jumping from 10 in 1990 to 28 in 2014, according to the latest UN report on world urbanization.
The total number of people living in megacities has grown from 153 million to 453 million during that period, the report says, and such areas now account for 15 percent of global GDP. Many are located in Asia: Tokyo, Japan, now tops the list in terms of population with 38 million inhabitants, China alone has six megacities, and India is projected to have seven by 2030.
Although densely populated urban areas can be environmental blights, innovations in efficient transportation have arisen from some major cities in Asia and Lagos, Nigeria, because those cities have invested heavily in public transit infrastructure, researchers say.
