"Yet a series of innovative environmental initiatives have improved the lives of its citizens and led to it being ranked as the world's top eco-city in the Quality of Living survey 2010 by human resources corporation Mercer. Calgary scored highly due to its excellent water quality and availability, waste removal systems, sewage systems and low levels of air pollution and traffic congestion. Based on these criteria, Calgary topped the index with a score of 145.7." (Quoted from article)