Six meters under ground, a group of workers are busy laying heating pipes in Xianyang, Shaanxi province, Nov 1, 2012. The narrow space forces them to crouch low, while the poor ventilation and pungent air test their lungs.

The workers come from all over the county. Welder Hao He's hometown is in Anyang, Central China's Henan province. Hao used to be a senior technician at a state-owned enterprise before it went bankrupt. Now he makes 4000 yuan per month.

A steel pipe is 12 meters long and weighs 766 kilograms, requiring four strong workers to carry them. After sanding and welding, the pipes ensure the heating supply for tens of thousands of families.

Workers prepare to check a heating pipe in Xianyang, Shaanxi province, Nov 1, 2012. [Photo/CFP]