Vienna, Austria's grand capital on the Danube river, has topped consulting firm Mercer's list of cities offering the highest quality of life for the eighth year in a row, while Baghdad is again considered the worst place to live.

Meanwhile London, together with other global centres Paris, Tokyo and New York City did not even make the top 30, lagging behind most big German, Scandinavian, Canadian, New Zealand and Australian cities. The England and UK capital ranked 40th, two spots behind its French counterpart.

The survey of 231 cities helps companies and organisations determine compensation and hardship allowances for international staff. It uses dozens of criteria such as political stability, health care, education, crime, recreation and transport.

Singapore was the highest ranked Asian city, at 25 while 29th-placed San Francisco was the United States' highest entry. Top of the list in Africa was South Africa's Durban at 87.