In order to pursue suistainability city planning including provision of electricity, water sewage, waste management, infrastruture, public services, education and governmance. Challenges Attribute represents the barriers and obstacles related to the establishment and implementation of Suistainable City initiatives, due to the social, economic, political, etc. environment. Like Values and Drivers, Challenges is part of the suistainable City context and is likely to change together with this context. A number of policy papers elaborate and in some cases provides concrete values to this attribute. Concerning social challenges, the fast growth of cities will give rise to significant inequalities in productivity and income inside and across cities, and between rural and urban cities (Commission On Growth And Development et al. 2009). As a result, policymakers will face political and ethnical tensions which must be balanced with economic benefits. The tensions and dificulties in achieving eficient urban development, which entails some kind of equilibrium between wage, cost of living and labor supply, lead developing countries to resist fast urbanization, viewing it as unmanageable pathology. According to (ISO 2013a), cities must provide quality of life to their citizens, while simultaneously dealing with the pressures of population growth, urbanization and climate change.
Concerning environmental challenges, generation of waste is rapidly increasing in quantity and complexity along with the urbanization growth – the solid waste will reach a peak in 2100, and collecting and disposing such waste will have a tremendous impact on municipal budgets (Commission On Growth And Development et al. 2009). According to the World Bank (The World Bank 2013), the carbon emissions due to urban transport will increase exponentially as demands for private transportation in developing countries will grow. New transport policies to provide viable alternatives to automobile transport are required, as is the need for cities to reduce carbon emissions. Cimate change adaptation and resilience, however, are not yet integrated in urban planning.