The Global Air Quality Report, which came out earlier this year, draws on data from more than 30,000 monitoring stations operating in 134 countries, territories, and regions. Of these, 124 countries exceeded the safe levels of PM2.5, a type of microscopic particulate matter capable of piercing the lungs and bloodstream, as defined by the WHO. These particles have been linked to heart and lung diseases, high blood pressure, increased risk of asthma, depression, anxiety, and premature death.

Countries yhat met the WHO Air Quality guidelines

Researchers used a color-coded scale to indicate pollution levels, placing many European nations in the green category, representing up to double the safe standard. Seven countries met the guideline of the WHO of five micrograms per cubic meter of air (μg/m3) or less. These include:

Australia
Estonia
Finland
Grenada
Iceland
Mauritius
New Zealand

Besides, Puerto Rico, Bermuda, and French Polynesia also attained safe air quality levels. In Europe, Iceland was the cleanest with 4 μg/m3, followed by Estonia at 4.7 μg/m3 and Finland at 4.9 μg/m3.

Countries with the least air pollution

Other countries with relatively low air pollution levels include:
Sweden, Ireland, Norway, Portugal, Liechtenstein, Denmark, the UK, Andorra, Latvia, Ukraine, the Netherlands, Luxembourg, Switzerland, Germany, Belgium, France, Austria, Spain, and Russia. Notably, European cities showed significant improvement from the 2022 report, with 54% classified as green in 2023, compared to just 39% the previous year.

Air pollution in other European countries

Countries in the yellow category, meaning up to three times the safe standard, include: Lithuania, the Czech Republic, Hungary, Malta, Slovakia, Bulgaria, Croatia, Poland, Cyprus, Slovenia, and Italy.

The highest progress was achieved by Croatia in 2023, with a more-than-40% reduction of PM2.5 compared to 2022, thanks to the increased utilization of renewable energy, reaching more than 31% of the energy mix, far above the EU average of 23%. Croatia has also moved to ban the use of coal by 2033, reduce methane emissions by 30% from the 2020 level by 2030, and put an end to deforestation by the same year.

In the orange category, which means up to five times the safe standard, were countries like Moldova, Romania, Albania, Greece, Turkey, Serbia, and Montenegro.

Bosnia and Herzegovina showed an 18% reduction in PM2.5 levels in 2023 compared to 2022 but remains the most polluted country in the region, followed by North Macedonia. Both countries are in the red category, with pollution levels over five times the safe standard. In Turkey, Iğdır is the most polluted city in Europe, with PM2.5 levels exceeding nine times the safe limit.

The world’s most polluted countries

Countries with the worst air quality are concentrated in South and Central Asia, where the world’s 10 most polluted cities are also located. Bangladesh topped the list with 79.9 μg/m3-more than 15 times the WHO annual guideline for PM2.5.

Pakistan was second, with pollution levels 14 times above the safe standard, followed by India at 10 times the limit. India also hosts the four most polluted cities globally, with the industrial city of Begusarai in the northeast being the worst. Tajikistan and Burkina Faso ranked fourth and fifth, respectively, with PM2.5 levels nine times above the safe threshold.

It is for the first time in six years of IQAir reports that Canada became the most polluted country in North America, hosting the 13 most polluted cities in the region.

Immediate action called for

Air quality reports act as important calls to action to reduce the levels of pollution, which are often the worst in areas where the vulnerable and underrepresented populations reside. However, the lack of data across many African nations leaves one-third of the continent’s population without access to air quality information.

“Clean, healthy, and sustainable environments are a global human right,” said Frank Hammes, Global CEO of IQAir. “In many parts of the world, the lack of air quality data delays decisive action and perpetuates unnecessary human suffering. Air quality data saves lives,” he stressed.

The fact that efforts to address cross-border smog and to decrease reliance on fossil fuels as a source of energy are not being taken is underscored by Aidan Farrow, senior air quality scientist at Greenpeace International.

“In 2023, air pollution remained a global health catastrophe,” added Farrow. “The IQAir global dataset is an important reminder of the injustices that result and how many solutions available for this problem need to be enacted,” he concluded.