London - The world's most expensive city for expatriates is Luanda, the Angolan capital, according to a study conducted by Mercer.
The African city thus beats even the famously over-priced cities such as Tokyo, Moscow, Geneva, Singapur or Oslo.
The second most expensive city is Tokyo, and the third N'Djamena in Chad.
Importantly, Brazil's Sao Paulo has made it to the first ten, pointing to the growing cost of life in the metropolises of the "Third World", and raising another doubt whether this term is still applicable.
The least expensive metropolis, according to the study, is Pakistan's Karachi, with costs of livings for expatriates being three times smaller than in Luanda.
The position of Prague, the Czech capital, remains unchanged from the previous study - it is the 47th most expensive city in the world. In Europe, it is the 14th.
The Mercer study explains that the position of a city is determined by two key factors: the strength of the city's national currency vs the US dollar over the prior 12 months, and price movements compared to those in New York over the same period. If the national currency gets stronger and/or prices get higher, the cost of living for the city's expatriates increase.
The study is aimed at transnational companies in order to help them estimate the expenses of their employees in different countries.
The authors of the study stressed the high number of natural disasters and political turmoil that occurred during the 12-month period covered by the study, which influenced currency exchange rates and caused price increases, above all of gasoline.