The sun seen through a thick haze over Thailand this week. The pollution is caused by the traditional burning of crop land in Sumatra, Indonesia. Photograph: Madaree Tohlala/AFP/Getty Images

The Thai holiday island of Phuket has been plunged into a poisonous grey haze caused by illegal forest fires in neighbouring Indonesia. Reduced visibility caused passenger planes from Singapore and Kuala Lumpur and destined for Phuket airport to turn around on Thursday. The noxious fumes which have been spreading for weeks have shut down many other parts of south-east Asia. Schools have been closed in Malaysia and races in Singapore for the swimming world cup – the FINA world championship – were cancelled on Saturday. A marathon in Malaysia on Sunday was also abandoned. The Thai foreign minister on Thursday invited Indonesia’s ambassador for a meeting to discuss the forest fires, the Bangkok Post reported. Pollution rose to 200 microgrammes on Wednesday evening, classed as “very unhealthy”. Don Pramudwinai said before his meeting with ambassador Lutfi Rauf that he wanted short and long-term solutions to a problem that is repeated annually during Indonesia’s dry season when plantation owners slash-and-burn land on Sumatra, the paper said.