Swiss climate group reveal cities with the best (and worst) air pollution

Swiss climate group IQAir have ranked cities around the world according to WHO guidelines for air quality. Photo / Unsplash

When considering what city to visit, the destination's attractions and activities, cuisine and accessibility feature highly.

It's unlikely we would ever spare a thought to a city's air quality. Yet, in places like Delhi, breathing the air can be equivalent to smoking 33 cigarettes a day due to air pollution.

Unsurprisingly, India's capital has experienced serious health issues related to toxic air but they aren't the only city battling bad air quality.

The World Health Organisation estimates 90 per cent of the world's population live in areas with harmful air quality. Since 2005, WHO said an average PM2.5 (inhalable particles with diameters 2.5 micrometres and smaller) of 10μg/m3 was 'healthy'. In October 2021, this was reduced to 5μg/m3.

The cities below thoroughly exceed these limits according to the World Air Quality Report by Swiss climate organisation IQAir.

Cities with the worst air quality

Hotan, China
This city was at the top of IQAir's 2021 list. Its average PM2.5 was 110.2. For context, the air is deemed 'safe' to breathe at 50 and under. Industrial sources of pollution are major issues however, the primary contributor to low air quality is the severe dust storms that often hit the city.

Delhi, India
Of the 10 most polluted cities in 2020, 9 of them were in India. Rounding off the list, behind Ghaziabad, Bisrakh and Kanpur was Delhi. The city reportedly had an average PM2.5 of 84.1 yet hit 157.3 in December.

Lahore, Pakistan
In spot 18, Lahore came out of 2021 with an average air quality rating of 79.2, hitting severe peaks of 151 and 161 in November and December.

Dhaka, Bangladesh
'Most polluted country in the world' probably isn't a title anyone wants, however, unfortunately, it's one Bangladesh has been given by IQAir. In particular, Dhaka's vehicle emissions, dense population and brick kilns result in the low air quality of 77.1 for 2020.

Cities with the best air quality

Waimea, USA
At the very bottom of the list (which is a good place to be considering what it measures), is the tropical Hawaiian village of Waimea, also known as Kamuela. With a population of 9,200 and very little development, it's no surprise the air is measured at 2.2; as clear as the tropical ocean.

St Helens, Australia
Coming up close behind with a PM2.5 of 2.4 is the game fishing capital of Tasmania, St Helens. Despite being the largest of Tasmania's northeast coastal towns, the air quality is one of the best in the world.

Muonio, Finland
Seven places up is the Finish city of Muonio, with an air quality score of 2.8 and a tiny population of 2,300. Located above the Arctic Circle, the municipality is famous for having the longest snow season in Finland and 24 days of continual daylight between December 10 and January 2.

Rothesay Bay, New Zealand
To find New Zealand, one has to scroll a touch further up the list, where the unsuspecting suburb of Rothesay Bay has a PM2.5 of 3.8. Found in Auckland's East Coast Bays region, it's fair to assume that this high-quality air score can be found around Tamakai Makaurau.