So what? Well, urban poverty challenges the development community in several ways. For a start, most development professionals have been trained in rural development and rural livelihoods. As we are so fond of saying, context is everything; whether we are equipped to face the different challenges of urban contexts is another question.
So how is urban development different? There's not enough research to be definitive, but there are plenty of plausible hypotheses.
For the hypotheses and the full article, see The Guardian here.