There is one area of Sao Paulo which is masterfully engineered... you can see it in the photos Bononi posted. That area is downtown, the area with all of the skyscrapers. However, most of Sao Paulo is one massive concrete block of poorly engineered urban development, too fast to even keep up with itself. To add to that, Sao Paulo has one of the highest homicide rates in the world. Basically everything surrounding downtown, north, south, east, or west, are small, run-down, dingy, drab, poorly-maintained neighborhoods and favelas. The same goes for New Delhi... the track (Buddh) itself is beautiful, and so is the airport, but New Delhi itself is a crime-ridden, smelly, heaving, polluted hellhole... poorly engineered, poorly maintained, poor overall. I have studied urban planning and geography... there are pockets of high-tech, ultra-modern urban areas in every city (except maybe Dhaka, Bangladesh!), including New Delhi and Sao Paulo, but it is no place for Formula 1.
Those buildings you see are all in one, semi-large space... Downtown Sao Paulo. That's where those skyscrapers, the Cathedral, the bridge, and the final photos are. Otherwise, urban sprawl. Most of the downtown is in need of some rebuilding, too. It is basically consisted of boring, gray skyscrapers with dirty windows and foundations eroding from acid rain.
Again, I hope I didn't offend anyone. Brasilia would be the perfect place to host F1, I think... near the government (where the money is), with a bunch of land, and a lot less crime. Rio is also an option... still lots of crime, but better looking buildings and a lot more tourists, plus the 2014 World Cup and the 2016 Olympic Games.
Here are some photos of the bad side of Sao Paulo.
Favelas
Pollution
Traffic