In June of 2008 it was reported that the top 5 cities with the best air quality in the world were as follows: number one is Zurich in Switzerland then the second through fifth were the four following cities: Vienna in Austria and Geneva in Switzerland both registered 107.9 points to come in at second and third. The fourth of the top five cities with the best air quality is Vancouver Canada. Finally, the fifth of the five cities with the best air quality is Auckland, New Zeeland. The rating system that these five cities were ranked by was Mercer Consulting. After the fifth city of Auckland, there were three consecutive German cities with the best air quality. The three German cities are Dusseldorf, Munich and Frankfurt. Baghdad is the lowest rated city on the list of cities with best air quality.
In the UK, while London ranked at 38 both Birmingham and Glasgow were together at 56. In the United States of America Honolulu ranked at 28.
Mercer Consulting based the scale on a point-by-point scoring index. This point by point scoring had Zurich with 108.0 points while Baghdad only scored 13.5 points. The cities were all based on a comparison with New York with an index score of 100 points. This quality of living scale ranks 215 cities around the world. The scale is used by various companies to place employees in cities for international assignments.
On the North American continent, the list was dominated by Canadian cities including Montral ranked at 22 up to Vancouver ranked at 4. After Honolulu, ranked 28 in the United States of America the U.S. cities fall down to New York ranked at 49.
In Central and Southern Latin America San Juan, Puerto Rico is the highest ranked at 72 only to fall down as far as Port au Prince in Haiti ranked 202.
European cities pretty much dominated the scale with Zurich in Switzerland ranked number 1 overall ending at Minsk in Belarus at 183. Switzerland and Germany are both represented in the top ten overall rankings with three cities from each country. Switzerland had Zurich ranked number 1 and Geneva ranked along with Vienna in Austria both scoring 107.9 points. You can say that Switzerland has the top two ranked cities with best air quality.
In the middle east and Africa Cape Town ranked at 80 and the cities in the Middle East and Africa with best air quality dropped all the way to the bottom with Baghdad, which was ranked as the worse at 215.
The Asia Pacific region of the world started with Auckland in New Zeeland that was ranked at five and went as far down as Jakarta which was ranked 146.