Do you have any verified source behind your claim? Because it is highly unlikely to happen given the overall mentality of Chinese government around cryptos. So a source must be cited before causing unnecessary panic!

However, if it happens, then bitcoin will be at risk! I know plustoken had ciphoned out few billion dollars worth bitcoin from the investors' pocket and later seized by the authorities. But I don't think China is planning to buy a majority of bitcoins to control its pricing. But since the Chinese government is evil by nature, it's not impossible!