Cleanest cities in the world (air quality)

Ranked purely on our environment score: air quality and pollution levels.

303 cities ranked

Overview

Reykjavik tops our ranking of cleanest cities in the world (air quality) at 10.0/10, just ahead of Zurich and Geneva. Choosing where to live is easier with numbers in front of you than with a gut feeling. Cleanest cities in the world (air quality) is exactly that: a data-driven answer, not a listicle opinion. Ranked purely on our environment score: air quality and pollution levels. This is a single-criterion cut of the entire 303-city database: every city is ranked strictly on cleanest, with no other factor pulling the order around. Average safety across this list sits at 6.8/10 and average climate at 6.3/10 — both well above a random sample of world cities, which says as much about the filtering as it does about any individual entry. Reykjavik posts the strongest individual safety score in this group at 10/10, a detail the blended ranking above can obscure if safety happens to matter more to you than to the average reader. Use this as a single-lens view rather than a final verdict: a city near the top here can still rank poorly once cost of living or climate are added back into the picture. The full ranking, full scorecards and links to each city's dedicated page are below.

Top pick

Reykjavik

10.0/10 overall

Most affordable here

Sofia

9/10 cost score

Average safety score

6.8/10

across 303 cities

Full ranking

Curious how the top two stack up criterion by criterion? Compare Reykjavik vs Zurich directly →

Methodology

This is a pure single-criterion ranking: every other factor is set to zero weight, so a city's position here reflects nothing except its score on cleanest. Want different priorities? Set your own weights in the recommender.

Understanding the criteria

Cleanest alone decides the order here. A city can score poorly on every other criterion — cost, transport, healthcare — and still top this specific list if it's strong on cleanest, so treat it as one input rather than a complete picture.

Tips for using this ranking

→Cross-reference with the overall livability ranking before deciding — a city that's #1 here on a single criterion can still be a poor all-round pick.
→If two or three cities are within half a point of each other, the difference is small enough that other factors (visa rules, flight connections, a language you speak) should probably decide.

Who this ranking is for

This ranking is most useful for Budget-conscious movers — movers for whom affordability outweighs every other factor, Safety-first movers — people relocating somewhere unfamiliar who weigh personal safety above all and Balanced movers — people without a single dominant priority, weighing all criteria evenly. If none of those match your situation, the recommender tool lets you set your own weights instead of relying on any preset list.

Best for budget-conscious movers

Valencia

Best for safety-first movers

Zurich

Best for balanced movers

Zurich

Strengths & limitations of this ranking

What this method gets right

+Nothing but the one named criterion affects the order, so it's a clean, unambiguous answer to a single-factor question.
+Every city in the database is included, not a curated shortlist, so there's no selection bias in who's eligible.

What it doesn't capture

−Optimizing for one criterion can hide serious weaknesses elsewhere — always check a city's full scorecard before deciding based on this list alone.
−A small gap between two cities (under half a point) is well within the noise of any scoring system like this one.

How are these scores calculated?

Every city on CityMatch is scored 1-10 on seven criteria — cost of living, safety, environment, transport, climate, healthcare and internet — and those seven numbers are combined into the overall score shown throughout the site using a consistent, automated formula (an equal-weighted average by default, or your own weighting via the recommender tool). The same method is applied identically to every city, so scores are comparable across the full database.

Sources & data provenance

The current dataset is an internally curated starter dataset built for this version of the site, reflecting each city's general reputation on each criterion rather than a live feed from a single external provider. It is not yet sourced from a specific third-party API. If that changes, this section will be updated to name the exact sources in use.

Last updated: 17 July 2026

Frequently asked questions

Which city ranks #1 for "cleanest cities in the world (air quality)"?

Reykjavik tops this list with a score of 10.0/10. The next best are Reykjavik, Zurich, Geneva.

What's the most affordable city on this list?

Sofia is the most affordable, scoring 9/10 on cost of living (10 = cheapest).

What's the safest city on this list?

Reykjavik posts the strongest safety score here at 10/10, ahead of the 302 other cities on this list.

How is this ranking calculated?

Every city gets a 1-10 score on cost of living, safety, environment, transport, climate, healthcare and internet. This list's average safety score is 6.8/10 and average cost-of-living score is 6.2/10 across 303 cities.

Is this ranking kept up to date?

Yes — every score on this page is recalculated automatically from the same underlying dataset each time the site is rebuilt, so the ranking always reflects the current numbers rather than a static, one-off list. See the "How are these scores calculated?" section for the full methodology.

Related rankings

Safest cities in the world Cheapest cities in the world Cities with the best climate in the world Cities with the best public transport Cities with the best healthcare

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