12 ITU‐T's Technical Reports and Specifications 1 Introduction In the last 50 years, the world population has grown exponentially at an average rate of 1.2% per year. In 2007, for the first time in the history of mankind, the number of people living in cities surpassed the number of people living in rural areas. It is estimated that the proportion will exceed 70% by 2050. As the UN World Economic and Social Survey 20131 suggested, Africa, Asia, and other developing regions will be housing an estimate of 80% of the world's urban population in the coming years. In the period from 1950 to 2010, small cities saw a net increase of 1.3 billion people, while medium cities (632 million) and large cities (570 million) saw about half as much growth1. Given the avenues of socio‐economic development that urban areas have to offer, migration to urban cities has become synonymous to opportunities and prosperity for millions of people around the world. As a result, urban areas are getting more and more congested. Along with the associated natural population growth, local and national policies, and environmental changes, urban migration and congestion are expected to be continuous trends. While urbanization brings advantages, it also brings challenges. Rapid urbanization adds pressure to the resource base, and increases demand for energy, water, and sanitation, as well as for public services, education and health care. Consequently, social, economic and environmental issues have become tightly interconnected. Cities greatly contribute to environmental degradation on local, regional, and global scales. Studies have demonstrated that they are accountable for 70% of global greenhouse gas emissions as well as 60‐80%2 of global energy consumption3. The obvious question is: how can cities be made sustainable under such underlying conditions? The answer lies in making cities 'smarter' by efficient management of resources and infrastructure, greener environment, and smart governance resulting in a better quality of living of its citizens. All of which can be enabled by the effective use of information and communication technologies (ICTs). ICT tools have the ability to provide eco‐friendly and economically viable solutions for cities. Potential advancements could be made in the forms of efficient water management based on real‐time information exchanges, public transport systems organized through information gathered by satellites, exploring solutions to concerns related to air quality monitoring and electromagnetic fields, among others. This is where the concept of smart sustainable city comes into play. 1.1 Scope Despite the wide range of literature that exists on the topic of global smart cities, there is a lack of agreement on the definition and on the specific parameters that characterize a smart sustainable city. Therefore, a comprehensive view of SSCs is vital to foster the consensus and consistency needed to advance the articulation of strategies, practice and research in this field. In response to that need, this Technical Report seeks to: (1) provide an overview of the main attributes that make cities smart and sustainable, (2) explore the role and potential of ICTs within ____________________ 1 http://www.un.org/en/development/desa/policy/wess/wess_ current/wess2013/WESS2013.pdf 2 http://www.unhabitat.org/downloads/docs/E_ Hot_ Cities.pdf 3 http://www.un.org/en/sustainablefuture/cities.shtml