Presumably, a broken BGP advertisement. These days, they create breathless "news" stories like this one. Back in the '90s, when small-town ISPs managed to accidentally advertise short paths to huge chunks of the Internet, they broke the whole Internet. It's hard to get too wound up about it.

If you're worried that China is going to MITM your SSL sessions, remove their certificate from your cert store.

If I was a Chinese supercyberspy, I probably wouldn't do something as blatant as routing the entire Internet to China just to get traffic I wanted. I think I'd do something much more akin to spearphishing an overseas Google employee to get onto their internal network.