There isn't one single country with the "cleanest" city, as rankings vary by criteria (air quality, waste, sustainability), but Singapore, Japan (Tokyo, Osaka), and European cities like Copenhagen, Helsinki, Vienna, and Zurich frequently top lists, highlighting strong national efforts in cleanliness, sustainability, and excellent urban management.
In 2023, the following ranking was determined based on these criteria:
Which is the Cleanest Country in the World: New Rankings
1. Copenhagen, Denmark. Copenhagen, often regarded as the world's cleanest city, has prioritised sustainability in its urban development. With a population of about 1.99 million, Denmark's capital has established measures that put it at the forefront of worldwide environmental initiatives.
The World's Cleanest Cities in 2025: Singapore Tops the List Again According to Travel + Leisure, the quest for spotless streets and pristine air has crowned Singapore as the cleanest city in the world for 2025.
LOOK: SINGAPORE, DAVAO, AND KUALA LUMPUR LEAD 2024 LIST OF CLEANEST CITIES IN SOUTHEAST ASIA Singapore continues its reign as the cleanest city in Southeast Asia, topping the 2024 Mid-Year Pollution Index by global data aggregator Numbeo, with an impressively low score of 32.5.
Cleanest countries in the world
San Jose earned the top spot as is the greenest city in the U.S., partially because it has the fifth-highest number of solar panel installations per capita. According to WalletHub, more than 47% of the city's electricity comes from renewable sources, the fifth-highest percentage in the nation.
Top 10 Best Countries to Live in 2025
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.
Cities which are rich in greenery and nature
The cities that lead our rankings, places like Folsom, (California), Newton (Massachusetts), Centennial (Colorado), Pleasanton (California) and San Ramon, (California), aren't just prosperous; they are exceptionally effective at delivering on the promise of a high quality of life for their residents.
Smart Cities prioritise environmental impact reduction and the green economy to create and maintain healthier, more sustainable places to live and work. Almost three quarters of European citizens now live in cities and this figure is expected to reach 80% by 2050.
These are the countries with the cleanest drinking water in the world:
Israel sees itself having multiple sources of pollution, which are further compounded by geographical and meteorological conditions, such as its arid or semi-arid climate and desert like environment, as well as a rapidly growing population coupled with a lack of natural resources.
Almost 99% of the world's population is exposed to air pollution, breathing air that exceeds WHO's safe guideline limits. Air pollution contributes to 6.7 million premature deaths every year, with low- and middle-income countries most affected.
GEO-7 foresees a slight drop in air pollution by 2050. But because of increasing urbanization, the absolute number of people exposed to airborne pollutants will rise. By 2050, 4.2 billion people will regularly inhale dangerous levels of one particularly problematic substance, PM 2.5.