The 30 Cleanest Cities in the World

Calgary, Canada

Calgary has been regularly ranked among the world’s cleanest cities in the past few years, and there is a good reason for that. Local people are taught 5 basic principles to follow in order to keep the environment clean and healthy. Those 5 points are Sewage System Quality, Water Drinkability and Availability, Waste Removal and Recycling, Traffic Congestion, and Air Pollution.