When Li Ming left the Chinese countryside and moved to the city to look for work more than 30 years ago, gruelling manual jobs were plentiful.

Three decades later, the 56-year-old is still hauling goods up and down the steep hills of Chongqing as one of the southwestern city's "bang-bang army", men and women equipped with nothing more than bamboo poles or carts, and muscle power.

China's economic boom was largely built on the backs of people like Li, with little or no education who earned low wages but were able to provide a marginally better life for their children.

They are among the last remaining vestiges of the start of China's rise, and have been largely replaced with trucks and electric scooters, where delivery men are employees of corporate logistics companies, not guns for hire.

These days most "bang-bang" are over 50.

"I don't have enough education to change jobs, this is the only work I've known since I came to the city," Li told AFP as he waited outside a wholesale market for customers. "No young people want to do this work, it's too hard, so all the 'bang-bang' are very old."

A study by Chongqing University in 2010 put the number of "bang-bang" at between 300,000 and 400,000, but locals dispute the claim. Most bang-bang interviewed by AFP said there were no more than 10,000 still working, with sharp declines in recent years as logistics companies have expanded.

As a heat wave gripped Chongqing in late August, many streets were empty as residents headed indoors in an attempt to keep cool. But despite the temperature reaching 42 degrees celsius (107 degrees fahrenheit), the army of mostly men, chests bare, lugged wares up and down hills, with most trips costing just 15 yuan ($2.25).

When business is good Li can make as much as 80 yuan a day, he said, but recently he has only managed to earn about 30 yuan a day.

Their competition is ever present in the streets of Chongqing. Boxes for household appliances, bedsheets, shoes and electronics are piled high on the pavement, waiting to be transported by electric tricycles or delivery vans.

"The young people that work for the courier companies are lazy," Li said. "A 'bang-bang' is always there when you need him, but a courier will deliver things only when it's convenient for him."

-- This story accompanies a photo essay by Nicolas Asfouri --