Chinese shares continued to fluctuate amid thinner turnover on Tuesday as investors were prudent. The benchmark Shanghai Composite Index went down 0.14 percent, or 3.04 points, to finish at 2,183.07. The Shenzhen Component Index shed 0.17 percent, or 14.20 points, to close at 8,365.35. Total turnover on the two bourses shrank to 187.65 billion yuan (30.79 billion U.S. dollars) from 200.06 billion yuan the previous trading day. Shares of Sinopec, China's top oil refiner, continued to tumble following the deadly pipeline blasts that has killed at least 55 people. It closed down 2.68 percent. Seven people from Sinopec and two local officials have been put in police custody after the explosions in eastern China's Qingdao City, police said on Tuesday. Other big losers included shares related to development zones and media and entertainment stocks. Bucking the trend, Ningbo and Zhoushan-related stocks soared on expectation for the approval of a free trade zone covering coastal Ningbo City in east China and nearby Zhoushan Islands. Ningbo Marine Co. and Ningbo Fuda Co. rose by the daily limit of 10 percent to 4.13 yuan and 5.17 yuan per share respectively. Ningbo Port Co. spiked by 9.84 percent to 2.79 yuan per share. Shares in medical equipment, electronic devices and shipbuilding also performed well, with the sub-indices tracking the sectors up 2.69 percent, 2.62 percent and 2.51 percent respectively. The ChiNext Index, tracking China's NASDAQ-style board of growth enterprises, dipped 0.15 percent to close at 1291.85 points.