Concern over degradation of coral reefs and the marine ecology of the Similan Islands caused by polluted water discharged into the sea, has prompted the Department of National Parks, Wildlife and Plants Conservation to prrohibit indefinitely overnight accommodation on the islands as of Tuesday.

The order was signed by Mr Tunya Netithammakul, the department head on October 4 and became effective as of Tuesday.

However, tourists on scuba diving trip will be allowed to stay overnight on the islands provided that they have prior permission from the Similan Islands national park.

The islands are still open to tourists for daytime visits.  The number of tourists visiting the islands is limited at 3,850 a day to prevent overcrowding.