Based on recent data (2024/2025 reports), Chad often ranks as the country with the worst overall air quality due to extremely high PM2.5 levels, followed closely by Bangladesh, Pakistan, and the Democratic Republic of the Congo, with many cities in India also experiencing severe pollution, though India's national ranking can vary slightly depending on the metric. These nations consistently see PM2.5 concentrations many times higher than World Health Organization (WHO) guidelines, with Central & South Asia being a heavily polluted region.
Top 5 most polluting countries
Australia generally has good air quality, but some events and industries can impact our air. Australia generally experiences good air quality. However, air quality can be reduced by specific events (which release pollutants for a short period) or specific industries (which affect the local area).
Listed below are 10 of the world's cleanest cities, each paving the way toward a more sustainable future for our planet.
You know that saying, “Come down for air” – aka Tasmania's catchy tourism slogan? Well, you might want to take it seriously, as Hobart came out on top as the city with the lowest air pollution levels in Australia and the third lowest in the world.
Australia is unlikely to become entirely uninhabitable soon, but climate change is making large areas, especially in the north, extremely hot and potentially unlivable under higher warming scenarios (around 3°C), straining infrastructure, impacting agriculture, and displacing vulnerable populations, while coastal areas face rising sea levels and severe erosion, making parts of cities and towns uninsurable and at risk. The primary threats are extreme heatwaves, bushfires, droughts, floods, and sea-level rise, disproportionately affecting regional, Indigenous, and disadvantaged communities, forcing significant adaptation and threatening the nation's food security.
Australia has been ranked among the cleanest countries in the world, with air quality considered the purest globally. This recognition comes from international environmental indexes that measure pollution, air quality, and sustainable practices.
Denmark is ranked as the cleanest and most environmentally friendly country in the world, thanks to its strong focus on renewable energy, waste management, and sustainable urban planning. With extensive wind power usage and eco-friendly policies, it sets a global example for environmental conservation.
99% of people breathe air that exceeds World Health Organization's guideline limits. Source: WHO. 9 out of 10 deaths attributed to outdoor air pollution are in low- and middle-income countries.
51% of India's air pollution is caused by industrial pollution, 27% by vehicles, 17% by crop burning and 5% by other sources.
1. San Juan, Puerto Rico. First on our list of cities with the cleanest air in the world comes the capital of the tiny Caribbean island nation of Puerto Rico. Locals and tourists alike can enjoy air with a PM2.
However, life expectancy at birth will be almost 90 by then. Australia will be bigger, older, denser and even more multicultural in 20 years time! Some 'Aussie Dreams' will have disappeared such as the 'quarter acre block' and along with it the Hills Hoist garden shed and enough space for a game of backyard cricket.
Cons:
The survey also asked respondents which state or territory will be the safest place to live as the climate changes. Tasmania is the clear winner, with two in five Australians (41 per cent) choosing it, with other states falling well behind.
Hobart, Tasmania, is widely recognized as the cheapest major city, but smaller regional towns in Queensland and South Australia can offer even lower living costs.
Perth has surpassed Sydney as the least affordable capital city in Australia, relative to household incomes. Albo''s legacy -poverty & antisemetic violence.
Toorak – The Undisputed Richest Suburb in Melbourne
From multi-million-dollar mansions to elite private schools and exclusive shopping strips, it has long been regarded as the richest area in Melbourne. Toorak is also home to Australia's wealthiest business leaders, celebrities, and international investors.
San Bernardino, California, ranks as the dirtiest city in the U.S. according to LawnStarter's 2025 report. Several other San Bernardino County cities, including Ontario, Fontana, Victorville, Rancho Cucamonga, and Apple Valley, also ranked poorly.
Here are some simple ways to protect yourself from air pollution: