ITU‐T's Technical Reports and Specifications 35 data from social networking services (SNS) (e.g. Twitter), web archives, and scientific databases, which are collected and accumulated via the Internet from various individuals and organizations. A smart city should have carried out risk assessment with respect to its susceptibility to various natural disasters and should have a strategy in place to deal with natural disasters to which it is highly susceptible. Cities worldwide are placing increasing importance on building up resilience to natural disasters. These include flooding, extreme weather, as well as heat and water stress, all linked to climate change. Sophisticated ICT infrastructure combined with analytical capabilities aid smart cities confronted by natural disasters to manage the information flow. This may be between multiple public agencies, such as transport authorities, emergency services and energy providers, and citizens. City municipalities may rely on mobile networks to reach the majority of its citizens at short notice.64 The Organisation for Economic Co‐operation and Development (OECD) published a study in 2010 estimating that major coastal cities including Miami, New Orleans, Tokyo and New York, would rely on flood defences to protect as many as 150 million people by 2070.65 A smart city's disaster resilience solutions should cover observation systems, information gathering capabilities, data analysis and decision‐making aids. These components matched with an intelligent and interoperable warning system will enable cities to respond effectively to natural disasters. This heavily depends on the municipality's uses of ICT infrastructure, including mobile networks, to efficiently receive, process, analyse and redistribute data, and mobilize various city services. 4 Conclusions The end goal for a smart sustainable city is to achieve an economically sustainable urban environment without sacrificing the comfort and convenience/quality of life of citizenry. A smart sustainable city strives to create a sustainable living environment for all its citizens through the use of information and communication technologies (ICTs). The various attributes of a smart sustainable city need to be identified and can be used as part of the metrics and reference points for defining the smartness and the sustainability of a city. This will help contribute to a better, more in‐depth understanding of what constitutes a smart sustainable city. While the actual development of key performance indicators (KPIs) for a smart sustainable city is outside the scope of this Technical Report, The latter does provide however some background towards the identification and development of such KPIs. A separate detailed report on such KPIs has been prepared by the ITU‐T FG‐SSC Working Group 3. What a smart sustainable city is depends on the \"lens\" or viewpoint from which one looks at a city. There are three key dimensions for a city, each of which has a number of attributes: Environment and sustainability – Related to city infrastructure and governance, energy and climate change, pollution and waste, and social, Economy and health. City level services – Viewing through an \"urban\" lens, there are multiple aspects and indicators including: technology and infrastructure, sustainability, governance and economics. ____________________ 64 http://www.gsma.com/connectedliving/wp‐content/uploads/2013/02/cl_ SmartCities_ emer_ 01_ 131.pdf 65 http://www.rms.com/publications/OECD_ Cities_ Coastal_ Flooding.pdf