Let's start from Chinese stock market: It has been tightly regulated by Chinese government and price was not going up and down freely. From this moment when Chinese government devaluation yen by 1.7% Chinese stock market showed its impact and stock price fluctuated in spite of government trying to keep it stable.
Bottom line is: Chinese stock is no longer in government hand and first time in history it acted freely as it should be in free market. But there is no perfect free market or perfect competition as we study in Economics.
Even Dow Jones or SP are partially influence by rich stock holder, somehow they know more than general public know and somehow some point it can be manipulated.
Think of Nepal: it can be manipulated easily by handful stockholders; I mean it can be influenced to some extent.