Helicopters dropped water and planes were deployed to induce rain as Indonesia stepped up efforts to extinguish forest fires that have caused choking haze, officials said.

Pollution indexes rose to hazardous levels in Indonesia’s Riau province, Singapore and Malaysia following days of forest fires, which have been blamed on plantation owners who practise illegal

slash-and-burn to clear land on Sumatra island.

“We’re working hard to put out the fires,” said Dody Rustandi, head of emergency response at the National Disaster Management Agency.

He said the number of hotspots dropped to 17 today, from 70 yesterday.

A C-130 Hercules and a smaller aeroplane would begin dropping salt-based chemicals into clouds to try to force out rain at noon, said Heru Widodo, the head of the Weather Modification Centre.

“We’ll send more aircraft if the fires intensify,” he said.

In Riau’s capital Pekanbaru, haze had blanketed the city for days, a resident said.

“The haze this year has been very bad,” said Santy Yeoh. “It was usually bad in the morning and cleared later in the day, but now it’s happening around the clock.”

“We are becoming very distressed by the situation and many people have begun suffering respiratory problems,” she said.

Riau’s provincial government yesterday declared a state of emergency in three districts worst affected by the smog, handing over the task of putting out the fires to the National Disaster Management Agency.

Environment Minister Balthasar Kambuaya said today that his ministry was investigating least 14 plantation companies suspected to have started some of the fires, the state Antara news agency

reported.

He did not name the companies, but said they included Malaysian firms.

Polluting the environment is punishable by up to 15 years in prison under Indonesian law.

- dpa