Geoffrey Payne in the year 1997 defined a slum as a heavily populated area characterized by sub-standard housing and squalor. It is applied to numerous settlement types in an area featured by social and economic isolation, irregular land ownership, and low standards of sanitary and environmental conditions. According to the UN-HABITAT report (2003), the slum is a contiguous settlement where inhabitants are characterized as having many inadequate housing and services.

In the Millennium Development Goals MDGs general context, a slum is defined as a wide range of low-income settlements and poor human living conditions; the inadequate housing conditions are manifestations of poverty. According to the government of Uganda in the year 2008 such issues such as sub-standard housing that are inadequate, insecure land tenure due to uncoordinated administration, uncollected solid waste dumping, drainage challenge.

Kenya Slum Upgrading Project (KENSUP) in 2004 and  Kenya Informal Slum Improvement Programme (KISIP) in June 2011, (Muragruri, 2012).  The core functions of these initiatives have improved the livelihoods of the people in relation to housing, empowerment, development of physical and social infrastructure, targeting to improve the livelihoods of at least 1.6 million households (5.3 million slum dwellers) by the year 2020.