In this picture taken on August 24, 2016 a "bang-bang" porter, also known as "stick-man" due to the bamboo sticks they use for carrying goods, walks up a street with a delivery receipt in his hand in Chongqing. 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. / AFP PHOTO / NICOLAS ASFOURI / TO GO WITH AFP STORY: CHINA-ECONOMY-LABOUR by Benjamin HASSNICOLAS ASFOURI/AFP/Getty Images

In this picture taken on August 24, 2016 a "bang-bang" porter, also known as "stick-man" due to the bamboo sticks they use for carrying goods, carries boxes of goods down steps in Chongqing. 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. / AFP PHOTO / NICOLAS ASFOURI / TO GO WITH AFP STORY: CHINA-ECONOMY-LABOUR by Benjamin HASSNICOLAS ASFOURI/AFP/Getty Images

In this picture taken on August 24, 2016 a "bang-bang" porter, also known as "stick-man" due to the bamboo sticks they use for carrying goods, rest in a street at dawn waiting for customers in Chongqing. 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. / AFP PHOTO / NICOLAS ASFOURI / TO GO WITH AFP STORY: CHINA-ECONOMY-LABOUR by Benjamin HASSNICOLAS ASFOURI/AFP/Getty Images

In this picture taken on August 24, 2016 a "bang-bang" porter, also known as "stick-man" due to the bamboo sticks they use for carrying goods, walks in a street at dawn in Chongqing. 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. / AFP PHOTO / NICOLAS ASFOURI / TO GO WITH AFP STORY: CHINA-ECONOMY-LABOUR by Benjamin HASSNICOLAS ASFOURI/AFP/Getty Images

In this picture taken on August 24, 2016 a "bang-bang" porters back is seen, as he takes a break carrying boxes, leaving bruises on his upper back in a street in Chongqing. 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. / AFP PHOTO / NICOLAS ASFOURI / TO GO WITH AFP STORY: CHINA-ECONOMY-LABOUR by Benjamin HASSNICOLAS ASFOURI/AFP/Getty Images

In this picture taken on August 24, 2016 a "bang-bang" porter use a towel to wipe off the sweat as he takes a break in a street in Chongqing. 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. / AFP PHOTO / NICOLAS ASFOURI / TO GO WITH AFP STORY: CHINA-ECONOMY-LABOUR by Benjamin HASSNICOLAS ASFOURI/AFP/Getty Images

In this picture taken on August 24, 2016 a "bang-bang" porter sweats as he carries goods on his back in a street in Chongqing. 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. / AFP PHOTO / NICOLAS ASFOURI / TO GO WITH AFP STORY: CHINA-ECONOMY-LABOUR by Benjamin HASSNICOLAS ASFOURI/AFP/Getty Images

In this picture taken on August 24, 2016 a "bang-bang" porter, also known as "stick-man" due to the bamboo sticks they use for carrying goods, walks in a street at dawn in Chongqing. 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. / AFP PHOTO / NICOLAS ASFOURI / TO GO WITH AFP STORY: CHINA-ECONOMY-LABOUR by Benjamin HASSNICOLAS ASFOURI/AFP/Getty Images