You either don't know what 50% means or you don't know that the total bitcoin hashrate for the past 3 months has been about 130 EHS. You also seem to be incapable of looking at the hashrate stats which shows that hashrate for the most part has been pretty much the same with normal ups and downs for the past 9 months. Even if you bothered looking at the recent hashrate in June you can see that it has gone up from about 118 EHS to 140 EHS.
On top of all that China doesn't even have 50% of the hashrate in total all around their vast country. Even if they banned bitcoin mining country wide (which they won't) the hashrate won't drop nearly that much.