From my armchair--it could be somewhere in between what's considered purchasing power parity and the actual exchange rate, because goods aren't exactly comparable when the entire supply chain is less advanced. You may pay less for a washing machine in a developing country, making your money go farther, but that washing machine may also have a greater chance of electrocuting you due to lower quality control. It's hard to measure quality of life through qualitatively similar goods. Is a jar of tomato sauce from a developed country that's vacuum sealed in a sterilized glass jar the same as a tin can of tomato sauce made under questionable conditions?

Edit: For Shanghai, cost of living is closer to 1:1 to 1:3 from here: https://transferwise.com/gb/blog/cost-of-living-in-china

A lot of officials have official salaries lower than median incomes, they just have expense accounts for up to a megabuck for a provincial level position, and more for ones in Beijing.