With fires burning out of control in Indonesia this fall, smog and haze have blanketed much of Southeast Asia. The region knows well the costs involved, and has even come up with a plan to deal with it. Unfortunately, Indonesia, the main offender, has not yet ratified the agreement. Action must be taken to end this annual catastrophe.

Farmers have long used fires to clear land for planting. In parts of Southeast Asia -- in Indonesia and Malaysia, in particular -- the technique is still popular. But the soil in those two countries is rich in peat, which can absorb heat and burn for a long time -- even when there does not appear to be a fire. The result has been a yearly blanket of smog that chokes residents, grounds flights and scares off tourists.

In 1997 and '98, the smog was the worst in history. Residents in Singapore, Malaysia and Indonesia were forced to stay indoors. Health costs soared and tourists canceled travel plans. The haze was so bad that the Malaysian government forbade publication of air-quality forecasts. The total bill is estimated to have reached $9 billion in lost revenues and higher health-care bills. That episode forced Southeast Asian governments to take the haze threat seriously. They responded with a 2002 agreement on Transboundary Haze, which lays out a multilateral action plan to deal with the problem. Indonesia's Parliament has not yet ratified the document.