The Chinese government is very good at one thing. That is, banning anything that could threaten the authority of the chinese government. That's why they banned Bitcoin, a decentralized cryptocurrency. Their central bank doesn't want competition.
Then, they banned ICOs. Then exchanges. And at last, they are banning Chinese miners. The good news is, there won't be a large impact of this in the crypto market. The bad news is, Chinese miners will get rekt. Or maybe not..
Update: Looks like the ban might have had a little impact. Bitcoin price went down from $5400 to $5150. That's not a significant impact. Some atl coins were hit hard but those with real use didn't get affected that much.