Award-winning director Nanfu Wang tells Sarah Catherall about what drove her to make a powerful indictment on China's one child policy.

Growing up in a small Chinese village in the 1980s, Nanfu Wang knew that her female baby cousin had died - but didn't know the circumstances.

Wang was born not long after the Communist Party's one child policy was introduced in 1979 and enshrined in the constitution in 1982. Everything in her village in the Jianxi province promoted the regime - school textbooks, calendars, posters, songs, television shows and theatrical works all espoused the doctrine that said single child