https://www.reuters.com/article/us-china-cryptocurrency-mining/crypto-miners-halt-china-business-after-beijing-cracks-down-bitcoin-dives-idUSKCN2D5031 >SHANGHAI (Reuters) -Cryptocurrency mining operators, including a Huobi Mall and BTC.TOP, are suspending their China operations after Beijing stepped up its efforts to crack down on bitcoin mining and trading, sending the digital currency tumbling.