The Global Liveability Survey is a measure of urban quality of life assessing stability, healthcare, culture and environment, education and infrastructure. It is published annually by the Economist Intelligence Unit.
Vancouver, Canada had been ranked first since 2002; however, the city has ranked third after Melbourne, Australia and Vienna, Austria since 2011. The EIU has stated that a highway closure on Vancouver Island (separated from Vancouver by the Strait of Georgia and not connected by bridge) resulted in the "small adjustment" to Vancouver's rating.
The Global Liveability Survey ranks 140 cities worldwide, and lists Damascus as the least livable city in the world in the latest index (August 2015).
References
The Economist Intelligence Unit's liveability survey Wikipedia(Text) CC BY-SA