Which challenges do you think are the most crucial ones with respect to African urban growth? 

African cities have grown with little or no consideration for their management. The rapid growth of urban centres in Africa has enormous socio-economic and political implications. These include the following, namely, uncontrolled disposition of wastes, noise pollution, congestion, youth unemployment, housing deficit, land scarcity, banditry, poor living and environment among others. Many urban cities in Africa are filthy and susceptible to epidemics. It is not an understatement if urbanisation is considered to be at the root of socio-economic and political crises in many African countries. Many of these countries has a phenomenon of excessive urbanisation partly due to the complete neglect of the rural areas in development planning and infrastructural provision which engendered rapid rural-urban migration. And rapid growth of urban population has in turn exacerbated socioeconomic and political problems all over the continent. 

Which are the most relevant social and economic aspects that need to be installed in urban structures to ensure sustainable development? 

The key social and economic aspects to be given consideration include the following: Policies must be put in place to stem the tide of rural-urban migration. There is need for a comprehensive development planning to ensure proper integration of the rural economy into urban systems for mutual benefits. Heavy emphasis should be on investment in infrastructural development. This is because the level of infrastructural development in a country is a very crucial factor determining the pace and diversity of regional as well as socioeconomic development. A well guided urbanisation is of utmost importance for efficient use of available resources. Also, a comprehensive agrarian reform policy should be put in place to foster industrialisation in the rural areas and engender growth and development. A well-developed land-use policy is necessary so that as many people that need land for productive purposes will have easy access to it. For urban development to be meaningful, it must enable all individuals, irrespective of sex, to increase their productivity and to participate fully in the process of income generation and remunerative employment.