Yay for the era of "alternative facts" and science that doesn't matter provided you get your daily pep talk from a news channel paid to tell you global warming is a commie lie.

I think you're talking about capitalism in general, not just China. Before regulations, EVERYONE did that kind of stuff. Why spend tonnes of money safely disposing of chemicals when you can just build your factory by the river and dump the chemical slurry into the water? There's no law against it, and it is very profitable.
All across North America and Europe this happened all of the time until regulations were enacted. Some waterways are still in their decades/centuries long recoveries.