2 and sustainable – encourages cities to adopt integrated policies and plans to build more inclusive, resource-eficient cities able to mitigate and adapt to climate change and improve their resilience to disasters. The promotion of Smart Sustainable Cities will be key to achieving these objectives, in addition serving the overarching objective outlined by Goal 13, to “Take urgent action to combat climate change and its impacts”. The new ITU-T Study Group 20 is developing international standards to enable the coordinated development of the Internet of Things (IoT), including machine-to-machine communications and ubiquitous sensor networks. The Study Group will develop standards that leverage IoT to address urban-development challenges, building on the 21 Technical Reports and Specifications compiled by this compendium. The Technical Reports and Specifications outline feasible means of developing Smart Sustainable Cities. They provide guidance to city leaders in establishing a framework for the management, control and optimization of the Smart Sustainable City environment as a laboratory for innovation and urban simulation. Such frameworks help us to improve our understanding of existing urban challenges as a basis for the development of efective responses to these challenges using coordinated urban ICT systems.This compendium also provides a detailed list of the key performance indicators (KPIs) for Smart Sustainable Cities developed by the Focus Group to assist city leaders in evaluating their degree of success in achieving the objectives of smart-city strategies. Dubai and Singapore were the first two cities to join ITU’s two-year pilot project to evaluate the feasibility of the KPIs, and ITU has been approached by a range of other cities interesting in joining the project. The pilot project will contribute to ITU’s international standardization of the indicators and the subsequent development of a ‘Global Smart Sustainable Cities Index’ derived from this set of indicators. This compendium is part of ITU’s eforts to support city leaders in their eforts to improve their understanding of the capabilities of Smart Sustainable Cities and the urban-development challenges motivating their development. ITU is commited to assisting cities in defining and executing long-term strategies for the development of Smart Sustainable Cities, and we are pleased to present this compendium in service of this commitment. Shaping smarter and more sustainable cities | Striving for sustainable development goals ITU-T’s Technical Reports and Specifications