Shares in two of China's biggest mobile gaming companies, Tencent and NetEase, fell more than 10% in the Hong Kong stock exchange, with investors worried about China cracking down on gaming companies.

State-run Economic Information Daily published an article saying that teens have become addicted to online gaming, mentioning Tencent's popular game Honor of Kings, and that students were playing it up to 8 hours a day.

"No industry, no sport, can be allowed to develop in a way that will destroy a generation," the article said before calling these games a kind of "spiritual opium." Tencent said it would introduce measures to reduce access and time spent on Honor of Kings after the article was published. 

The article was later deleted from China's WeChat platform, prompting Tencent's shares to recover. The company also saw its shares plummet last week after it was ordered to end its exclusive music licensing deals with international record labels. This came as part of a general policy aimed at tackling its dominance of online music streaming (more than 80% of China's exclusive music streaming rights).