(Yicai Global) Dec. 19 -- Chinese mainland stock markets tumbled this afternoon, taking the three main indexes to more than six-week lows.

The Shanghai Composite Index fell 1.05 percent to 2,549.56, its lowest since Oct. 30, with a trading turnover of CNY93.7 billion (USD13.6 billion). The Shenzhen Composite Index closed down 1.48 percent at 7,418.69, marking a new low since Oct. 31 after investors swapped CNY123.4 billion worth of shares.

The ChiNext Price Index, which tracks growth enterprises in Shenzhen, finished the day down 1.90 percent at 1,268.81, its lowest since October 31, with CNY38.8 billion worth of share swapping hands.