"The outcome is that the urban pattern becomes more segregated, more differentiated.
In many African countries, those at risk often have to spend huge amounts of money and travel hundreds of miles to reach heart specialists concentrated in main urban centres.
For Herbert Girardet, the author of a dozen books on urban theory, this isn't the most urgent concern.
But in Egypt, even the best urban plans have tended to go awry.
So, to get a better idea of what it takes to create a winning urban app, we caught up with one of the co-founders of Colab, Bruno Aracaty... When, and how, did you first have the idea for the Colab app?
We recently announced the launch of this year's AppMyCity! competition to find the world's best new urban mobile application.
"The idea, visually, is to be light skin and dark skin, urban, rural and remote from all different parts of Australia, so there is a balanced visualisation of what Aboriginal women look like," Quilliam tells Guardian Australia on the road from Ntaria to Alice Springs.
For India's middle class, Italian coffee has replaced sweet chai as the drink of choice and Social (9a-12 Hauz Khas Village, socialoffline.in) is an upscale, urban hangout with hotdesking facilities that does a good cup.
