This report, amongst many similar ones, talks about the existence of many cities superposed in a single city, layer over layer. If there are spatial layers signalling extreme inequality that exist side by side and over each other, there must be the people layers too: layers of super rich and super poor existing side by side and over each other.
While this unacceptable situation draws much attention, the overwhelming reaction it draws is human: the plight of millions needing help and support, the plight of the unsustainable city, the plight of injustice.
There is, however, an economic question that should be asked: the layer most seen and most neglected is the layer that provides massive amounts of informal services to the city too. What are the economic (and sustainability) returns of the removal of trash and recycling in Brazil, or those of the millions of shopkeepers, farmers, construction workers, taxi drivers, street vendors, rag pickers, tailors, and repairmen in Dharavi Mumbai? The statistics and distribution of space and density in which these economic activities are carried out makes one think of the ratio of the amount of spatial and economic resources consumed per capital to the economic output that is produced.
Then, provision of a decent standard of housing for millions of people would not remain a question of provision, it would turn into the same policy idea that now says: if you invest a lot in big business, the benefits trickle down to the millions. Maybe we should formally compute the economic returns from millions of people in terms of the services they provide, and think of a policy perspective that says: invest in the smallest of businesses and decent living, education, and health environments for millions, since the economic benefits of these services trickle down as well as up to all the inhabitants of the city. Because even without the computations, it is perhaps clear, that the benefits of the super big are not trickling down to the informal and often largest parts of the city.