There are one billion slum dwellers worldwide and an additional 3 billion people will need adequate housing by 2050 as population increases and people move to cities and urban centres. In spite of progress made in improving or preventing the formation of new slums, the absolute number of slum dwellers is growing, and is expected to increase threefold by 2050 to almost half of the world’s urban population. Slums are sometimes located in environmentally degraded or hazardous locations, exposing inhabitants to flooding, erosion, natural disasters and climate change-related phenomena.