A hot air balloon has exploded and crashed in southern China, killing four Dutch tourists and injuring three other people. State media said the balloon had only been in the air for about an hour, and was descending when it erupted into flames. The explosion is thought to have been triggered by a gas leak. The crash occurred 30 kilometres south of Yangshuo in the southern province of Guangxi. Five tourists from the Netherlands and two Chinese balloon pilots were on board. It is thought that the four dead were two couples. An investigation into the accident is under way.