Mercer states that it "evaluates living conditions in more than 450 cities worldwide for expatriates and their families who work outside their country of origin", as reported by NM.

"Living conditions are analysed according to 39 factors, grouped into 10 categories: political and social environment, economic environment, sociocultural environment, medical and health considerations, schools and education, public services and transport, leisure, consumer goods, housing and environment".

The overall ranking is led by Vienna, which maintains its top position, followed closely by Zurich, in second place, with Auckland and Copenhagen occupying third and fourth positions, respectively. Geneva completes the top five positions.

Lisbon and Porto appear in 39th and 55th position in the global ranking, respectively. Considering only European cities, Lisbon is the 24th European city with the best quality of life while Porto occupies the 33rd position.

In the list of most environmentally friendly cities, Lisbon and Porto appear in 45th and 67th position, respectively.

According to the Mercer ranking, the global positioning of Lisbon and Porto "contributes to the fact that Portugal is facing a housing crisis, worsened by the rise in inflation, which leads to a limited supply of properties for rent, making it difficult to find affordable accommodation", states the note.