Air quality plunged to "very unhealthy" levels across parts of Malaysian Borneo today as haze from fires raging in Indonesia thickened across the region.

Fourteen other areas in Malaysia, including the capital Putrajaya and the largest city, Kuala Lumpur, recorded 'unhealthy" air quality, while only three out of 51 monitoring stations recorded "healthy" air.

Schools in Indonesian provinces on Borneo island closed and masks were distributed to residents.

Flights have also been affected, with some airlines canceling services. Earlier this week a plane skidded off a runway in eastern Borneo in poor visibility.

"It's dark and gloomy outside," Sri Laraswati, a hotel worker in the Indonesian city of Pontianak on Borneo, told the Guardian. "Most people are wearing masks. People are coughing and staying inside. Visibility is a few hundred metres at best."

The smoke comes from hundreds of brush, forest and peat fires across Sumatra and Borneo. Most are thought to have been started deliberately as a cheap and quick way to clear land, but experts say some - especially on peaty land - could have started by themselves.

The late start to the rainy season across many parts of Indonesia is also a contributing factor. The US government warned yesterday that the developing El Niño weather pattern in the Pacific Ocean, which usually brings drier weather across much of south-east Asia, would linger into next year.

Malaysia's environment minister, Azmi Khalid, accused Indonesia of not doing enough to solve the problem in today's Star newspaper. "I was in Jakarta in June and met the relevant ministers," he said. "They told me they had the systems to control the haze. It looks like their system is not effective."

Mr Azmi urged Jakarta to sign a regional agreement on the issue, but Indonesian officials claim they are working tirelessly to stop the haze.

"We are doing what we can, including cloud-seeding, but the problem is there are too many hotspots," Hoetomo, the deputy minister for environmental compliance, told the Associated Press. "Indonesia is a large country and the haze just hangs in the sky. We are hoping that rain will pour heavily soon."