Adams EA, Price H & Stoler J (2019) Urban slums, drinking water and health: Trends and lessons from Sub-Saharan Africa. In: Vojnovic I, Pearson AL, Asiki G, DeVerteuil G & Allen A (eds.) Handbook of Global Urban Health. The Metropolis and Modern Life. London: Routledge, pp. 533 - 552. https://www.routledge.com/Handbook-of-Global-Urban-Health/Vojnovic-Pearson-Gershim-Allen-DeVerteuil/p/book/9781138206250
First paragraph: One of the biggest challenges facing humanity is the achievement of water security, i.e. ensuring sustainable access to safe, affordable, reliable and accessible supply of drinking water for all. Over the past three decades there has been significant progress: 2.6 billion people gained access to improved drinking water between 1990 and 2015, and 147 countries met their Millennium Development Goal (MDG) target to reduce by half the population without access to an improved water source (WHO and UNICEF 2015). Despite this progress, approximately 663 million people worldwide still lack access to improved drinking water sources, with substantial regional variation in coverage, and urban-rural disparities (WHO and UNICEF 2015). Even though 96% of global urban dwellers now use improved sources, the brunt of urban water insecurity falls disproportionately on residents of urban slums, defined by the United Nations (UN) as “urban areas without basic services such as safe water, sanitation, electricity etc., and characterized by poor housing, overcrowding, insecure tenure, and social exclusion” (UN Habitat 2013; UNSD 2015).