Of the 150 cities ranked, four out of the top ten most stress-free cities are in Germany. The southern city of Stuttgart comes out on top, with Hanover in third place, Munich in fifth place and Hamburg in joint ninth place with Graz, Austria.
The tiny yet wealthy country of Luxembourg, home to fewer than 600,000 people, has the second-lowest stress levels.
Bern, Switzerland is fourth, while Bordeaux, France (No. 6) and Edinburgh, UK (No. 7) also make it to the top of the charts.
Sydney, Australia (No.8) is the only non-European city to break the top ten, while Seattle is the most chill US city.
Greenbacks and green spaces
The study, by UK-based dry-cleaning and laundry service Zipjet, was conducted by studying 500 locations based on data relating to 17 categories covering infrastructure, pollution levels, finance and citizens' wellbeing.
This determined a ranking of 150 cities with available data on all factors relating to the study.
The city ranked the most stressful overall is Baghdad -- with a total score of 10 compared with Stuttgart's one -- followed by Kabul.
Stuttgart's formula for worry-free living, meanwhile is having a strong local economy -- this is the home of Porsche, Bosch and Mercedes-Benz -- but also coming out top in the study for the highest percentage of green spaces within the city limits. The city is spread across a range of hills and valleys, some covered with vineyards.
Stuttgart's generous greenery "really [has] a noticeable effect on stress," says Stuttgart-based PR professional David Moos. "The ability to feel less enclosed can help you in not feeling stifled, and personally I find this reduces anxiety. The feeling of security in the city, both financial and in the sense of personal safety, is also a great comfort."
The formula for easy living
Public transport getting you down? Not if you're a Singaporean.
Luxembourg has the lowest population density after Kuwait City, and Sydney and Melbourne (No. 6 and No. 7) are also relatively uncrowded urban spaces.
Residents of Singapore and Taipei are most satisfied with their cities' public transport, while Leipzig, Germany and Montpelier, France have the lowest levels of traffic congestion.
In the security category -- in which the official average rates of theft and murder are weighted against United Nations data on the local perception of security per capita -- Abu Dhabi was judged the most "safe" place to live by its citizens, with Osaka, Japan in second place.
And while sunny weather is an instant mood-lifter all over the world, high levels of annual sunshine didn't count for much in terms of a city's overall ranking. War-torn Damascus came out top in that category, while Bordeaux -- at No. 56 -- was the sunniest city in the top ten.
North America came out tops in terms of low air pollution levels, with Miami, Seattle, Vancouver and Boston leading the way. Abidjan, in the Ivory Coast, has the lowest noise pollution, while Antananarivo, Madagascar, and Reykjavik have the lowest light pollution.
Reykjavik comes out best in the Physical Health and Gender Equality categories.
Phnom Penh has the lowest official unemployment rates and Brunei's Bandar Seri Begawan has the lowest debt per capita, but the real measure of a city's financial health is in the Family Purchasing Power category, which balances average household salaries with the cost of living.
Munich came out top by this criteria, followed by Luxembourg, Sydney, Monaco and Stuttgart.
Athens scored best in the Social Security category but, with rioters taking to the street earlier this year to protest increases in tax and social security contributions, it may be what the Ancient Greeks described as a Pyrrhic victory.
Luxembourg, Bordeaux and Graz performed best in the Mental Health category, while Reykjavik has the best record for Physical Health. The Icelandic capital also comes out tops when it comes to gender equality.
The race equality category -- based on data from a World Bank ethnic inequality report -- is, perhaps surprisingly, topped by cities in the US. San Francisco, Boston and Seattle take the top three slots.
Glamorous, global cities such as London (No. 70), Tokyo (No. 72), Paris (No. 78) clustered around the middle of the league table, with New York (No. 84) being the most stress-inducing of the big four.
The world's least stressful cities
1. Stuttgart, Germany
2. Luxembourg City, Luxembourg
3. Hanover, Germany
4. Bern, Switzerland
5. Munich, Germany
6. Bordeaux, France
7. Edinburgh, UK
8. Sydney, Australia
9. (tie) Graz, Austria and Hamburg, Germany
The world's most stressful cities
1. Baghdad, Iraq
2. Kabul, Afghanistan
3. Lagos, Nigeria
4. Dakar, Senegal
5. Cairo, Egypt
6. Tehran, Iran
7. Dhaka, Bangladesh
8. Karachi, Pakistan