What I found interesting here is that the more I read the article, the more I found striking smilarities between Sao Paulo and Mumbai with Lagos, Nigeria. It is Africa's largest city.
Like these two cities, Lagos is home to an estimated 21 million people, it is Nigeria's commercial capital. Like these two cities as well, Lagos faces rapid population growth due to massive rural-urban and even urban-urban migration, pressure on infrastructure and public services, an underclass living in the fringes of the city etc. I can bet that there's a proliferation of insulated gated communities where the upper middle class lives in these cities, just as in Lagos.
The state governor, Babatunde Fashola has made significant strides in cleaning up and rehabilitating the city through infrastrucutal upgrades (currently building an intracity railway), urban renewal intiatives etc which is attracting massive inflows of investments. It is the only state in Nigeria where the poverty rate is below 30% - the national average is 62% according to World Bank figures (48% according to the National Bureau of Statistics).
You should include Lagos in a similar assessment next time.