The benchmark CSI 300 Index, which tracks A-shares listed in Shanghai and Shenzhen, dropped 107 points, or 3.1%, to close at 3,386 on Thursday, putting it on course for its biggest weekly decline on record, Bloomberg reported. The index has fallen 10% this week so far and 37% this year. Analysts attributed the drop to a reserve requirement ratio hike announced by China’s central bank on Tuesday. All 10 of the index’s industry groups fell yesterday. The Shanghai Composite Index fell 2.1% to close at 3,223 yesterday while the Shenzhen Composite Index fell 3.2% to close at 971.