Yes, many times previously I have stated the opinion that China's environment could mean the end of the country as it now exists. That isn't necessarily totally bad, but social unrest in the world's most populous country, especially something like a civil war (which is unlikely but not completely impossible) would be, to put it mildly, an event. More likely is some serious effects on the economy, and because of the massiveness of the Chinese economic engine, that could be a problem, too. Seriously.
Michael Friedman goes in deeper depth on this. I'm providing two links to the same article because the first one direct to the NY Times might not work.
Too big to breathe (NY Times)
China gets too big to breathe (Salt Lake Tribune)
"China has built amazing hardware in 30 years — modern cities, roads, airports, ports and telecoms — bringing more people out of poverty faster than any country in the history of the world. The Chinese have much to be proud of. Every healthy economy, though, depends on a healthy environment. China will stall if President Xi Jinping and his government do not now build the software — the institutionalized laws, courts and norms — to ensure that all this growth will not be undermined by an epidemic of despoiled land and dirty air."
That pretty much nails it.