He's far closer with 40% than 10%
94 blocks in the last 24h make it a 34% drop.
So yeah, thinking this as only one province it's highly possible they could kill at time 50% to maybe 60% of the hashrate, doing this on the first day of an epoch and then turning it on for the next then again off would mess up the network pretty bad. As for the price, China doesn't matter there, maybe they could in the past by manipulating numbers on exchanges with fake orders as Okex was used to do but those times are gone.

And for the most important part:

I don't think there are traders left that believe what officials from China say one day carry any weight tomorrow, they have contradicted themselves so many times in the past and have made statements that have never been backed by laws or government measures that right now everything that comes from China is probably taken as a short time price jump in any direction and nothing more.