Shares of Chinese companies listed in the US have seen their biggest two-day fall since the 2008 financial crisis.
The index has now plummeted by more than 45% since hitting a record high in February.
The slump comes after a series of crackdowns by Beijing on its technology and education industries.
This has led to around $770bn (£556bn) being wiped off the value of US-listed Chinese stocks in the last five months alone.
The latest blow came as Beijing unveiled a massive overhaul of China's $120bn private tutoring sector, under which all institutions offering tuition on school curricula will be registered as non-profit organisations.
The new rules also said: "Curriculum subject-tutoring institutions are not allowed to go public for financing; listed companies should not invest in the institutions, and foreign capital is barred from such institutions."
Chinese authorities are also cracking down on a wide range of online services from food delivery apps to music streaming platforms.