Editor's note: This report focuses on Chongqing as part of our special series, "Rising Star Cities," about Chinese cities whose annual GDP exceeds 1 trillion yuan ($155.4 billion, or more than the GDP of Qatar). At the end of 2020, there were 23 such cities. Click here for more stories on Chongqing. You can also explore our earlier coverage of Ningbo and Changsha. 

The mountain city of Chongqing has bred generations of "Bangbang" porters, manual laborers who carry packages for travelers and merchants up and down the sloping villages. Bangbang refers to the pole the porters use.

But with the development of the express delivery industry and improved urban transportation, the Bangbang men are disappearing fast, with fewer than 2,000 left.