What is the largest city in the southern hemisphere?

What is the largest city in the southern hemisphere?Sao Paulo, with its 17 million people,is the largest city in the southern hemisphere.

Sao Paulo (20,200,000), Brazil

São Paulo - The city has an area of 1,523.0 square kilometres (588.0 sq. miles) and with 19 million people living in the greater metropolitan area, the city makes it the largest and most populous city in the Southern Hemisphere. However, when the many adjacent metropolitan areas, such as Baixada Santista, São José dos Campos, Campinas, Sorocaba, etc. are included, such as in the Extended Metropolitan Area (Complexo Metropolitano Estendido) São Paulo, there are nearly 29 million inhabitants, more than any other city in the world except Tokyo with 35 million.

* There are 25 megacities in the world as of October, 2005. See also the definition of megacity form the source.