An aerial view of the vast and blue Duncan Island which is part of the Crescent Group.[Photo/Xinhua]

To the southeast of Hainan, the Xisha is a cluster of islets, sandbanks and reefs, famous for their unusual tropical scenery and ecosystem.

The obvious appeal of these island paradises has led to unauthorized, and potentially disastrous, tours being spontaneously organized by nature lovers. In Jan. 2013, 24 travelers were stranded there for four days by bad weather.

Promoting tourism on the Xisha islands has been on the Chinese government's agenda for years. The State Council, China's cabinet, announced late in 2009 that Hainan would be developed as a destination for international tourists, including the Xisha Islands.

Sansha City, on Yongxing, one of the Xisha islands, was founded in July 2012 to administer about 2 million square km of islands, coastal areas and territorial waters in the South China Sea.

The city envisages tourism as its economic engine, and administers three island groups -- Xisha, Zhongsha and Nansha -- along with surrounding waters in the South China Sea.

Sansha, with its changeable maritime climate, vulnerable environment and limited supplies of basic necessities, can only cope with a very small number of visitors. Nearly everything has to be imported. The supply vessel Qiongsha III is the only lifeline, bringing things like fresh water and food from the mainland. It makes a round trip once a week, weather permitting.

Visitors often become ill because of the high temperature and other extreme conditions in the Xisha islands. Medical services remain inadequate, putting the safety of visitors at risk, said Cao Chengwei, executive director of the Haikou College of Economics.

To tackle the infrastructure problems, there are plans to construct ports, hospitals, power stations, sea water purification plants and sewage treatment works in Sansha. More ships are under construction to facilitate transport.