Chinese stocks continued to slide amid drastic fluctuations on Thursday as the key index struggled to hit the 3,300-point mark.

The benchmark Shanghai Composite Index went down 0.49 percent to close the day at 3,271.51 points, and the Shenzhen Component Index closed 0.63 percent lower at 10,552.96 points.

Trading remained thin, with total turnover on the two bourses standing at 407.7 billion yuan (about 61.3 billion U.S. dollars).

Excitement over China's mixed-ownership reform plan waned on Thursday, with China Unicom, which saw a rally following its scheme to introduce private investment, pulling back 6.7 percent to end at 8.36 yuan per share.

The telecom giant last Wednesday published a scheme to introduce private investment mainly by issuing shares to buyers, including China Life and Tencent, but then withdrew all relevant filings with Shanghai Stock Exchange due to "technical reasons."

The restructuring plan reappeared on the Shanghai bourse website Sunday night, followed by a supportive announcement from China Securities Regulatory Commission (CSRC).

Since trading resumed on Monday, shares of the company surged over 20 percent before falling on Thursday.

Shares related to environmental protection rose across the board as authorities released a guideline to stimulate development of equipment manufacturing for pollution control.

By 2020, the market value of environmental protection equipment should reach one trillion yuan, according to the plan released by the Ministry of Industry and Information Technology.

The ChiNext Index, which tracks China's NASDAQ-style board of growth enterprises, lost 0.64 percent to close at 1,795.74 points.