Definitions of cleanliness and a “clean” city can vary greatly. A clean city doesn’t necessarily mean one can eat off of the streets or sidewalks. A clean city can be a lack of trash in the streets, an abundance of clean water, or high air quality – or all three.
To be a clean city, the problems that lead to unsanitary and unhealthy living conditions need to be solved. This includes waste management, creating transportation infrastructure is using energy-efficient and green technology, preventing littering, and implementing policies that ensure cleanliness.
Pollution is a large factor in determining the cleanliness of a city. Pollution is the introduction of contaminants into the air and environment causing adverse effects. Pollution damages the environment and the human body as air pollution is a cause for lung cancer, cardiovascular disease, chronic obstructive pulmonary disease, and other serious health issues.
Due to a variety of factors, cities around the world experience different levels of pollution. For several years, cities have been working on green initiatives to implement cleaner means of transportation, processes, and lower the levels of pollution. In the United States, Congress passed several Clean Air Acts in an attempt to enforce stricter pollution regulations, resulting in dramatic decreases in pollution levels such as carbon dioxide emissions and particulate emissions.
Best Life analyzed 200 of the world's largest cities to determine which were the cleanest. The analysis included air pollution levels (both PM10 and PM2.5), the quality of life ranking according to Mercer, the country's Environmental Performance Index, and if the city has a spot on Monocle's Quality of Life survey. Not all cities on the list have a Mercer and Monocle ranking.
Based on these data points, the cleanest cities in the world (and their clean city scores) are:
The cleanest city in the world is London in the United Kingdom. London has an overall clean city score of 74.94 and an Environmental Performance Index score of 79.89. This is followed by Paris and New York City. New York City may come as a surprise to many considering it is the most populated and the most densely populated city in the United States with a population of over 8.3 million and a density of 27,755 persons per square mile.
Because about 55% of the world’s population lives in urban areas, making them the most densely populated areas in the world, keeping cities clean is a challenge. With the worldwide urban population expected to rise to 68% of the world’s population in the next few decades, both governments and residents need to work hard to preserve the cleanliness and quality of cities.