The 2023 World Air Quality Report provides a vital overview of global air quality, highlighting regions where pollution continues to pose serious health risks. By understanding what’s in the air we breathe, we can better protect our health.

Fortunately, there are shining examples of major cities that have achieved excellent air quality, serving as beacons of hope and inspiration for communities worldwide. By prioritizing the public’s health through anti-polluting policies, those communities are changing the urban narrative for the better – proving that big cities can enjoy clean skies.

Download the 2023 World Air Quality Report

Learn about the state of air quality around the world.

DOWNLOAD NOW

These five major cities have demonstrated exceptional commitment to clean air, with annual average PM2.5 levels meeting or nearly meeting the World Health Organization’s (WHO) stringent guideline of 5 µg/m3 or less. PM2.5, the most dangerous particle pollutant, is a key indicator of air quality due to its severe health impacts.

Apart from this selection of major cities, there were several smaller communities and cities with good air quality. For this list, the selected cities have both large populations and are familiar names to most people.

5: Stockholm, Sweden

In 2023, Stockholm, Sweden enjoyed an annual average air quality of 5.4 µg/m3, just slightly above the WHO recommended guideline. While there is room for improvement, Stockholm benefits from the city’s commitment to promoting public transportation and implementing green urban planning initiatives (1).

Sweden was the 11th cleanest country in the world in 2023, coming just behind regional neighbors Finland and Estonia with an annual average air quality of 5.1 µg/m3—again, very near the WHO guideline. Sweden emphasizes the use of renewable energy sources – the country has a stated goal of accomplishing 100 percent renewable energy by 2045 – and maintains stringent environmental regulations, helping to reduce air pollution (2).

Though heavily forested, Sweden did not experience many wildfires in 2023 (3), which helped keep wildfire smoke out of the capital.

Air quality in Stockholm, Sweden on June 7, 2024. Source: IQAir Map.

4: Sydney, Australia

In 2023, Sydney, Australia, with a population of 5.3 million, met the WHO's PM2.5 guideline with an annual average of 5 µg/m3. This was achieved through stringent air quality standards and proactive pollution control measures, despite occasional challenges from bushfire smoke.

Australia requires outdoor air quality standards to meet an annual average of 8 µg/m3, a standard the country more than met in 2023 with an annual average of 4.5 µg/m3 (4).

Bushfire smoke can negatively affect the city’s air quality, as was the case in late December, 2023 (5). However, such events were rare that year.

Air quality in Sydney, Australia. Source: IQAir Map.

3. Helsinki, Finland

Like its Scandinavian neighbor Sweden, Finland enjoyed good air quality in 2023. The capital city, Helsinki, was just below the WHO guidelines with an annual average air quality of 4.9 µg/m3. The credit can be given to the city’s robust efforts to preserve green spaces and reduce traffic emissions (6)(7)(8).

Finland was one of the few countries and territories in the world to average below the WHO guideline in 2023, again with annual average air quality of 4.9 µg/m3. That made the country the 10th cleanest country or territory in the world. Finland has a low population density, extensive forests, and strong environmental protections.

Air quality in Helsinki, Finland. Source: IQAir Map.

2. Melbourne, Australia

Melbourne, Australia experienced an annual average air quality of 4.4 µg/m3 in 2023.

Melbourne can be affected by bushfire smoke, industrial and mining activity, and transportation pollution. Nearby Victoria had a lower-than-average number of bushfires, thanks in part to a wet La Niña climate pattern (9). This further helped maintain the Melbourne’s good air quality in 2023.

Air quality in Melbourne, Australia. Source: IQAir Map.

1. Auckland, New Zealand

Aukland, New Zealand had the best air quality in 2023 among well-known major cities, with an annual average air quality of 3.4 µg/m3. Coastal winds, strict vehicle emission standards, and policies promoting public transportation all helped keep air quality clean.

The country was among the cleanest in the world in 2023, just above Australia (whose 2023 an annual average was 4.3 µg/m3) (10).

New Zealand was the 6th least polluted country or territory in the world.

The country benefits by its islands’ geography, with ocean breezes that carry local pollutants out to sea and no nearby neighbors to send transboundary pollutants nearby. The country receives a good deal of rainfall as well, which helps disperse pollutants.

New Zealand has improved on its air quality over the years, dropping from an annual average air quality 7.7 µg/m3 in 2018 and consistently decreasing the average each year.

Air quality in Auckland, New Zealand. Source: IQAir Map.

The takeaway

While these five cities set a remarkable example in 2023, it’s crucial to remember that no level of air pollution is completely safe. Continuous efforts are needed to mitigate pollution and protect public health. Regardless of where we live, we can all advocate for cleaner energy, support smart environmental policies, and contribute to air quality monitoring. By taking these steps, we can collectively work towards a healthier, cleaner future for everyone.