China vows zero doping tolerance for Rio

A top Chinese sports official says the country has committed to a zero-tolerance stance on doping ahead of the Olympics in Rio de Janeiro.

Vice Director of the General Administration of Sports Gao Zhidian told the official Xinhua News Agency on Thursday that Olympics-bound athletes and coaches were required to sign pledges not to cheat, saying violators would be severely punished.

Gao said athletes, coaches and team doctors must also pass a written exam on banned substances with only those scoring 80 per cent or more permitted to go to Rio.

China has sought to shake a reputation for doping following past scandals. That resolve was questioned when it emerged that officials waited six months before revealing champion swimmer Sun Yang served a three-month suspension after testing positive in May 2014.