Thailand is the fifth Asean country to be affected by what has become one of the world's longest running transnational environmental crises, one that is challenging the credibility of the 10-member bloc.
The haze from Indonesia enveloped southern Thailand, including Phuket, where flights were disrupted for the second day running yesterday. Of the tourists who visit Thailand - a number the government hopes will exceed 28 million this year - half of them visit Phuket and other nearby islands.
On Tuesday, Thai Prime Minister Prayut Chan-o-cha said Asean needs to address the issue.
Indonesia's Ambassador Lutfi Rauf met Thai foreign ministry officials yesterday and reportedly said the forest fires were too serious for Jakarta to handle alone and that it needed assistance. Thailand is expected to raise the issue at a meeting of Asean environment ministers in Hanoi from Oct 26-30.
While fighting the haze requires a mutual coordinated response under the Asean Agreement on Transboundary Haze Pollution, it has thus far turned the agreement into a relationship test. The underlying issue is the resolve of governments to deal with the consequences of irresponsible business practices. No government is immune. Bangkok had its own haze crisis earlier this year.
This year's transboundary haze will be worse than that in 1997, which cost the region an estimated US$9 billion (S$12.6 billion) - a figure already exceeded this year in Indonesia alone. The fires also contribute to greenhouse gas emissions, making nonsense of efforts to address global warming.
Patches of resolve are emerging. Indonesia has deployed thousands of soldiers to fight the fires. Companies thought to be responsible to some degree for the fires are being identified. Singapore has begun legal action against five companies.
The haze has demonstrated decisively that corporate social responsibility should be more than just a slogan, and that agreements need to be more than just words on paper.