At 3 am on April 24, 2010, a baby boy was delivered in a field hospital after a four-hour operation.

He didn't cry and his breathing was shallow. His face was covered in blood and his mouth was filled with meconium - an intestinal discharge that can block a baby's airways if breathed in prior to birth.

Obstetrician Zhang Hong-juan performed artificial respiration on the newborn immediately, ignoring shouted warnings from a midwife.