Disappointing economic data dragged down both the Shanghai and Shenzhen stock markets in the week's first trading day, giving back all the gains the two markets had achieved in the previous week.
The Shanghai Composite Index shaved off 2.73 percent, or 64.89 points, to close at 2,308.55, and the Shenzhen Component Index dipped 2.67 percent, or 271.29 points, to finish at 9,874.52.
The Shanghai Composite sank below its 180-day moving average, with the cement, construction materials, steel and coal sectors the biggest drags.
The transaction volume of the mainland's two stock markets reached 159.88 billion yuan ($25.12 billion), up by 8.51 percent from the previous trading day.
As crude oil prices in the global market continued to fall, two of China's largest oil giants, Petrochina Company Limited and China Petroleum & Chemical Corporation, both saw their stocks sag to a three-year low, closing at 9.30 yuan and 6.49 yuan per share respectively.
China's latest less-than-impressive non-manufacturing data has further stirred up concerns about the country's economic slowdown.
China's non-manufacturing purchasing managers index, one of the gauges for the country's economic activity, fell to 55.2 in May from 56.1 in April, the National Bureau of Statistics and China Federation of Logistics and Purchasing reported Sunday.
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