Rio de Janeiro
Rio has more people living in slums than any other city in Brazil, according to the 2010 Census. More than 1,500,000 people live in its 763 favelas, 22% of Rio's total population. São Paulo, the largest city in Brazil, has more favelas (1,020) in sheer numbers, but proportionally has fewer people living in favelas than Rio.
Demographics of São Paulo
São Paulo's population has grown rapidly. By 1960 it had surpassed that of Rio de Janeiro, making it Brazil's most populous city. By this time, the urbanized area of São Paulo had extended beyond the boundaries of the municipality proper into neighboring municipalities, making it a metropolitan area with a population of 4.6 million. Population growth has continued since 1960, although the rate of growth has slowed. In 2007 the city's population stood at 10,886,518 and it was estimated that 18.8 million people lived in the urban agglomeration.