Economist Intelligence Unit (EIU) makes comparisons with an Index where the cost of living in New York equals 100. On that index Zurich, the largest city of Switzerland, is the costliest city to live in the world as the score at index is 170 here.
The next costliest city is Tokyo in Japan where the score on the index is 166. According to EIU "Both Japan and Switzerland have seen strong currency movements over the last few years which have made them relatively more expensive".
Zurich which was in the 4th place last year had a swing in index of 34% and hence the top place. And it is the first time after twenty years that Zurich is in the 1st place surpassing Tokyo which most of the time held that spot.