Maybe the Chinese crackdown but I think Binance CEO do not relate his crypto business with his country China when he already experienced some issue back in 2017 or so that led him to move Binance out of the country to Japan. Although the reason is not yet clear, but I think it could just be a minor technical issue which will be solved soon.
Although China has been taking measures to prevent crypto activities in this country, however, I think it is not the cause that Coinmarketcap is not showing up now. Moreover, if China implements blocking of cryptocurrency activities, this activity will only be effective for internet users here, other places can still use it normally, the weird thing is I've been using it for most of the day today and haven't had any problems 