China doesn’t have as strong a government as many people would think. A lot of enterprising individuals and even local governments will do whatever they can get away with to make a few more yuan. They’ll only stop when the central government gets serious and cracks down.
But the same could be said for any hyper capitalistic society without rule of law or strong regulatory enforcement. That just happens to mainly be China right now, but could also be the USA in the future if the EPA is dismantled and Trumpism reigns.