Hong Kong is the overall most expensive ciy in Asia-Pacific and is the second most expensive city in the world (after Luanda) as at January 2018, mainly due to extremely high housing costs, as well as high cost of schooling and limited space available making rentals high.
Singapore remains the second most expensive city in the Asia-Pacific region for expatriates (3rd most expensive in the world) and tops the region rankings when costs related to housing, education, medical and transport are excluded.
Tokyo is the third most expensive city in Asia-Pacific, and 8th globally. Japanese locations have remained high in the rankings with 5 cities in the Asia-Pacific top 10 most expensive places.
Shanghai is the fourth most expensive place for expatriates in the Asia-Pacific region, and 12th globally.
https://www.xpatulator.com/cost-of-living-article/Asia-Pacific-Expat-Cost-of-Living-Comparison_709.cfm