The United Nations estimates that by 2030 there will be 43 megacities worldwide with more than 10 million inhabitants, compared to the 31 that currently exist.
This data is part of a recently published report by the United Nations which predicts that, by 2050, two out of every three inhabitants of the planet will be living in urban centers. This will necessitate better sustainable urban development plans, as proposed by the United Nations.
In absolute figures, the report's authors predict that by 2050, urban areas worldwide will have gained a total of 2.5 billion inhabitants.
Tokyo (Japan) is currently the most populated city in the world with 37 million inhabitants, followed by Delhi (India), with 29 million, and Shanghai (China), where 26 million people live. The next two cities in the ranking are from Latin America: Mexico City (Mexico) and São Paulo (Brazil), both with 22 million. The following graph shows the ranking of the 30 most populated cities in 2015:
It is estimated that in the year 2028, Delhi will become the most populated city in the world, surpassing Tokyo. And a few years later, in 2035, the forecast is that Delhi's population will reach 43 million inhabitants, surpassing Tokyo by 7 million.
The United Nations report estimates that three countries –India, China, and Nigeria– will account for 35% of the total urban population growth between 2018 and 2050. Specifically, India will add 416 million inhabitants to cities, China, 255 million, and Nigeria, 189 million.