Back in the 1950s, China's population was increasing by around 1.9% each year, after people were encouraged to have children to increase the workforce. But the government decided that this was unsustainable, resulting in the one-child policy. Those who flouted the rules were either fined, lost their jobs, or in some cases, mums were forced to abort their babies or be sterilised.
Some desperate parents gave up their babies, leaving them is so-called baby hatches. It was for poor mums and dads who could not afford to keep their sick or disabled baby and saw parents simply place a child in the hatch, press an alarm button and then leave them behind to be taken care of by the state.