Worsening haze from Indonesian fires

A street vendor sells masks on a street in the West Kalimantan provincial capital of Pontianak

JAKARTA, Indonesia -- A thick blanket of haze from almost 1,000 fires or hotspots in Indonesia is threatening to envelope more of Southeast Asia, already prompting health alerts to be issued in neighboring Malaysia.

The haze, caused by the illegal lighting of fires to clear land in Kalimantan and Indonesia's Sumatra island, has become an annual problem in Asia.

In 1997 and 1998, a choking haze from forest fires -- started from attempts at land clearing – shrouded parts of Southeast Asia for months, disrupting flights and causing serious health problems. It also created almost $10 billion in economic losses, officials have said.

Although the current situation is nowhere near as bad as four years ago, visibility in some areas of Indonesia has been reduced to less than 500 meters (1,650 feet).

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The situation is worsening after the number of blazes has almost doubled since Saturday and poor visibility has forced the cancellation of dozens of domestic flights.

In Malaysia, health authorities placed hospitals on alert for treatment of respiratory complaints.

The precaution was taken following government reports that the air quality in much of the state had "badly deteriorated."

Officials say they are monitoring the situation and have warned that if the haze worsens, they may have to advise residents to curtail outdoor activities.

The Malaysian government has stepped up surveillance to enforce its strict land clearing rules.