Four of the top 10 cities in this year's ranking are in Asia. The most expensive city in the region, Hong Kong, jumped from sixth place to third, followed by Singapore. Tokyo - previously Asia's most expensive city for expatriates - fell four places to seventh, while Shanghai came in 10th on the list, jumping four spots from last year.
"Rankings in many regions were affected by recent world events, including economic and political upheavals, which resulted in currency fluctuations, cost inflation for goods and services, and volatility in accommodation prices," said Mr Ed Hannibal, Partner and Global Leader for Mercer's Mobility practice.
"While Luanda and N'Djamena are relatively inexpensive cities, they are quite costly for expatriates since imported goods come at a premium. In addition, finding secure living accommodations that meet the standards of expatriates can be challenging and quite costly as well."
The survey covers 211 cities across five continents and measures the comparative cost of more than 200 items in each location, including housing, transportation, food, clothing, household goods and entertainment.