The haze is back.

Two years after Southeast Asia was enveloped in a debilitating smog--stinging lungs, forcing schools to close and causing chaos to shipping lanes and aviation routes--smoke from forest fires in the Indonesian provinces Sumatra and Kalimantan is once again blanketing the sky, raising questions about the government's resolve to contain what is becoming a perennial crisis.

In the last few weeks, schools have been closed in Riau province on Sumatra island, where a state of emergency was declared because of the haze. More than 300 people have been admitted to hospitals, mostly suffering from respiratory problems. And the haze is being blamed for the collision of a tanker and barge last week that left a dozen people dead.

Haze was already sending pollution indexes to record levels across the Malacca Strait in Singapore and Malaysia, where the world's tallest buildings, the twin Petronas towers, were obscured by smog, and in Brunei, which has threatened to sue Indonesia. The Association of Southeast Asian Nations (ASEAN) will hold a crisis meeting at the end of the month for regional environmental ministers to address the problem.

By week's end, rain had decreased the number of fires and reduced the number of "hot spots" visible by satellite. Schools in Riau were able to reopen. But environmental experts warned that the reprieve was only temporary: The areas being burned this year may be even larger than in 1997. With this just the start of the burning season, the region is once again facing an ecological and health catastrophe.

"It's just started," said Longgena Ginting, coordinator of the forest advocacy program for the Indonesian Forum for the Environment. "We're pessimistic about the fires this year, and we predict they will be bigger."

He said the underlying cause of the fires--blamed on the practice of large plantation of burning wooded land to clear it for planting--is Indonesia's rapid conversion of its forests to agricultural use. He said Indonesia is deforested at a rate of 12.4 million acres each year.

The World Wide Fund for Nature said it had identified 37 plantations in Sumatra and Kalimantan responsible for most of the fires.

Today, environmental groups said the number of hot spots in Sumatra was down to 128, from a high of 342 on Aug. 2; a hot spot is defined as 250 burning acres.

Many here accused the government of President B.J. Habibie of failure to take action to prevent the fires because it did not penalize agribusinesses identified as responsible for the latest round.

In 1997, when former president Suharto was in power, the government identified 176 companies suspected of involvement in the fires. But local environmental groups said none of those companies--some of which were politically connected to the ruling elite--was ever punished. The government blamed small-scale farmers for starting the fires, but investigations by local environmental groups found that 94 percent were caused by large plantations.

Longgena's group sued 11 of those companies in Sumatra and six in South Kalimantan, but both suits were dismissed when the courts said there was not enough evidence linking the companies to the fires.

Habibie, speaking at an environmental conference here last week, ordered immediate action to stop the fires, saying: "We must ensure that our forest is not burned because of our negligence. If this happens, our environment will be more damaged."

But critics said inaction by a weak government hobbled by other more immediate crises--from bank scandals to ethnic violence to separatist insurgencies--was precisely the problem.

"We have so many laws to prevent the fires, but none are effective," said Bambang Hero Saharjo, a forestry expert and consultant with the World Wide Fund for Nature. "Habibie has asked people to stop the fires. But if there's no implementation, then it's just words."

The ASEAN regional group has implemented a "haze action plan" to coordinate strategies for fighting the blazes, sharing information about the location of blazes and strengthening firefighting capabilities. A regular update on the fires is provided online (www.haze-online.or.id).

But even ASEAN concedes that the first job in controlling the blazes lies with Indonesia, and the government's response so far has been found wanting. "It's pretty slow," said Rodolfo C. Severino, the secretary general. "It's [a question of] resources. Plus, Indonesia is in a transition, so it's difficult to get its act together."

CAPTION: Smog from Indonesian fires obscures the Petronas Twin Towers, right, and the Kuala Lumpur Tower in the capital of Malaysia.