Premier Li Keqiang said regulators didn’t respond actively to declines
It was not known if Xiao's resignation offer had been accepted by the central government
China will intensify crackdowns on insider trading and manipulation by funds and curb speculation in equities and futures market.
China's stock markets have fallen around 40 percent since mid-June, spooking global markets and investors
The prohibition is also seen applying to foreign investors which hold stakes in Shanghai- or Shenzhen-listed companies.
The airstrip will be long enough to accommodate most Chinese military aircraft.