The plunge wiped almost $370 billion in market capitalization from the benchmark Shanghai Composite index .SSEC, which opened nearly 9% lower.
The yuan opened at its weakest level this year and slid 1%, past the symbolic 7-per-dollar level in onshore trade CNY=.
Oil, iron ore, copper and soft commodities traded in Shanghai all posted sharp drops.
The total number of deaths in China rose to 361 as of Sunday, and the number of infections to 17,205. Deaths had stood at 17 and infections at 600 when Chinese markets last traded on Jan. 23.