Photo taken on May 20, 2013 shows the scenery of Xuande Islands of Sansha City, south China's Hainan Province. (Xinhua/Zha Chunming)

Photo taken on May 20, 2013 shows the scenery of Coral Island of Yongle Islands in Sansha City, south China's Hainan Province. (Xinhua/Zha Chunming)

Photo taken on May 20, 2013 shows the scenery of a village on the Jinqing Island of Yongle Islands in Sansha City, south China's Hainan Province. (Xinhua/Zha Chunming)

Photo taken on May 21, 2013 shows the building of local government on the Yongxing Island in Sansha City, south China's Hainan Province. (Xinhua/Zha Chunming)

Photo taken on May 20, 2013 shows the scenery of the Chenhang Island of Yongle Islands in Sansha City, south China's Hainan Province. (Xinhua/Zha Chunming)

Photo taken on May 20, 2013 shows the scenery of Yongxing Island in Sansha City, south China's Hainan Province. (Xinhua/Zha Chunming)

Photo taken on May 21, 2013 shows the road scenery on the Yongxing Island in Sansha City, south China's Hainan Province. (Xinhua/Zha Chunming)

Photo taken on May 21, 2013 shows a sign of the "Beer Cultural Square" on the Yongxing Island in Sansha City, south China's Hainan Province. (Xinhua/Zha Chunming)

Photo taken on May 21, 2013 shows ships at a port of the Yongxing Island in Sansha City, south China's Hainan Province. (Xinhua/Zha Chunming)

Photo taken on May 20, 2013 shows the scenery of Yongle Islands in Sansha City, south China's Hainan Province. (Xinhua/Zha Chunming)

Photo taken on May 15, 2013 shows a road sign on the Yongxing Island in Sansha City, south China's Hainan Province. (Xinhua/Zha Chunming)

An engineer of the local meteorological authority tests the air temperature in Sansha City, south China's Hainan Province, May 21, 2013. (Xinhua/Zha Chunming)

Photo taken on May 20, 2013 shows the scenery of Lingyang Reef of Yongle Islands in Sansha City, south China's Hainan Province. (Xinhua/Zha Chunming)

Photo taken on May 20, 2013 shows a port of Yongxing Island in Sansha City, south China's Hainan Province. (Xinhua/Zha Chunming)

Photo taken on May 15, 2013 shows the scenery of Yongxing Island in Sansha City, south China's Hainan Province. (Xinhua/Zha Chunming)

Photo taken on May 21, 2013 shows road signs on the Yongxing Island in Sansha City, south China's Hainan Province. (Xinhua/Zha Chunming)