Because China is influential in the cryptocurrency industry with them recently holding the biggest mines in the world and with that the hash rate of bitcoin, and thus when they do something related to cryptocurrency, then be sure that it will affect the prices. Not to mention that they have a big population.
China does always make surprising news, this time by using its greatest strength as a bitcoin miner, China prohibits mining activities, and of course this has a big impact on the development of bitcoin. but I think this is only a problem for a moment, because it will soon grow back to normal, because on the other hand many people see this as an opportunity