The rapid growth of Rio de Janeiro's population has led to a severe shortage of housing. As a result, millions of people have been forced to construct their own homes from scrap materials such as wood + corrugated iron.
These areas of temporary housing are known as favelas in Brazil.
The conditions associated with favelas are very poor. E.g. no sewerage, no services, no electricity, disease is common and many people are unemployed.
Favelas are located on the edge of cities on marginal land because
this is the only available land to build on.
industry is located on the edge of the cities, so favelas locate here to be close to jobs
Land here is poor quality, usually on very steep hillsides + prone to landslides.