MOHD RASFAN / AFP / Getty Images The Kuala Lumpur skyline is covered by haze on June 27, 2013

The choking haze from forest and peat fires on the western Indonesian island of Sumatra is back. Last week, it reportedly started to blanket parts of Malaysia, reigniting fears that millions of people on both sides of the Strait of Malacca would again endure the days of record pollution they suffered in June. With August to October considered the peak period for forest fires, authorities have warned that the worst may be yet to come.

The haze that primarily engulfed Indonesia, Singapore and Malaysia this year is the worst experienced in Southeast Asia since 1997. And as in previous years, the fires were caused by the slash-and-burn land clearance commonly practiced in the region, a method that is cheap and extremely efficient but also illegal. Even as Singapore and Jakarta were engaged in a diplomatic spat over the forest fires, much blame has been directed at palm-oil and pulpwood companies. Comparing NASA’s satellite images and the Indonesian government’s plantation concession maps, the World Resources Institute, a nonprofit group based in Washington, D.C., concludes that half of the hot spots occur in pulpwood concessions and palm-oil plantations in Sumatra. As Jakarta vows to investigate, the big companies identified in the media, and in reports from green groups, deny their involvement in the fires, saying they have “zero burn” policies and blaming the haze instead on noncompany growers and small farmers in the supply chain. New evidence has emerged to show that the great majority of fires are started on small to medium-size plantations.

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Regardless of who torches the forest, this year’s haze has highlighted not only Jakarta’s inability to uphold the law but also its continuing failure to insist on the environmentally responsible conduct of the palm-oil and pulp-and-paper industries — two giant sectors of Indonesia’s economy that have long been accused of wreaking much damage to the country’s forests and wildlife and causing conflicts with local communities. “The smog roiling Indonesia and its neighbors is partly a result of Indonesia’s green growth strategy, which involves clearing forests for the rapid expansion of oil palm and pulp plantations,” says Human Rights Watch in the summary of this report, published in mid-July.

Indonesia’s swath of rain forest, mainly on the islands of Sumatra, Borneo and Papua, is the third largest in the world, but the area is disappearing fast as huge proportions are being handed over to palm-oil and pulpwood producers. It is vanishing so rapidly that Indonesia is now the world’s third largest emitter of greenhouse gas — after industrial behemoths the U.S. and China — with 75% of its emissions stemming from deforestation, forest degradation and damage to carbon-dense peatlands.

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The country is also the world’s largest producer of palm oil, a commodity that is used in many everyday consumer items from soap to lipstick, from chocolate to biscuits. It is also a major player in the pulp-and-paper industry. However, the toll taken by these industries on the habitat of the country’s diverse wildlife is devastating and could drive critically endangered orangutans, tigers, rhinos and elephants into extinction. Greenpeace and other green groups have used market and industry campaigns to target palm-oil and pulpwood companies, and big firms doing business with them, with considerable success. In February, Jakarta-based paper behemoth Asia Pulp and Paper (APP), among the world’s largest, announced a zero-deforestation policy, following a lengthy Greenpeace campaign that highlighted its role in environmental destruction and saw APP lose contracts with more than 100 major companies as a result, including deals with Adidas, Lego, Mattel, Kraft and Nestlé. APP’s decision followed a 2011 commitment by its sister company, palm-oil giant Golden-Agri Resources, to end forest destruction following a similar Greenpeace campaign that cost Golden-Agri its contracts with Burger King, Kraft, Unilever and Nestlé.

The naming-and-shaming strategy “can bring pressures on big brands like Nestlé, Unilever and Mattel to have a commitment to be responsible and to stop sourcing from those involved in or linked to environmental destruction,” Bustar Maitar, head of the Indonesia forest campaign at Greenpeace, tells TIME. “They need to clean up their supply chain and cancel contracts with suppliers that are involved with deforestation.”

(PHOTOS: Sumatra’s Orangutans Under Threat)

There has been a shift in attitude. Multinationals like Nestlé and Unilever have pledged to stop using palm oil produced from trees planted on land that was virgin rain forest, and European countries like the Netherlands, Belgium and the U.K. vow to import 100% certified sustainable palm oil by 2015. But that will be easier said than done. By industry estimates, sustainable palm oil accounts for only 15% of palm oil produced. The Roundtable on Sustainable Palm Oil (RSPO), the biggest certification scheme for palm oil, is meanwhile seen by environmentalists as lax and unable to enforce codes of conduct. With nearly 1,300 members, including the big players in the palm-oil industry, the RSPO was set up after the 1997 haze crisis. But critics say this year’s fire-and-haze disaster highlights the regulatory weakness of the voluntary international body — some of whose members have been linked to the fires. In response, several nongovernmental organizations, including Greenpeace, and some palm-oil producers (including major players like Golden-Agri), have set up a new coalition called the Palm Oil Innovation Group to lay down tougher standards.

Consumer sentiment in Asia — where India and China are the world’s top importers of palm oil — will be crucial, and there are some encouraging signs in this area. A 2012 survey by McKinsey found that 44% of Chinese consumers were willing to pay more for more environmentally friendly products. In Singapore, which suffers a great deal from the noxious effects of the haze, a local push to raise consumer awareness of so-called dirty palm oil is emerging. “If we can signal strongly to the companies that buy palm oil [to manufacture their] products that we are extremely unhappy and they are risking the wrath of consumers, then they can signal [that] to the palm-oil companies,” Lim Biow Chuan, lawmaker and president of the Consumers Association of Singapore, told the city’s Today newspaper.

The Greenpeace campaigner Bustar supports such a move. “That’s a simple thing that consumers can do,” he says. “They should help urge producers to stop getting supplies that are linked with deforestation.” Until they do so, the annual summertime forecast up and down the Strait of Malacca looks hazy for many years to come.