Indonesia has launched its biggest operation ever to combat the fires that have shrouded the region in stifling haze for weeks, deploying 32 planes and helicopters and thousands of troops for the battle.
The all-out blitz began yesterday even as Indonesian provincial police said they were investigating a South Kalimantan-based company owned by investors in China for illegal slash-and-burn operations.
"This is the biggest firefighting operations Indonesia has ever done," said Indonesian National Disaster Management Agency spokesman Sutopo Purwo Nugroho.
A total of 21 helicopters, seven fixed-wing aircraft for water-bombing, and four aircraft for cloud seeding are being deployed - six of them are from Singapore, Malaysia, Australia. They were dispatched to back up the more than 22,000 personnel on the ground who have been fighting the fires for weeks.
Dr Sutopo said the air teams would conduct water-bombing and weather modification efforts across six of the worst-hit provinces in Sumatra and Kalimantan.
Fires illegally started to clear land for plantations have blanketed Indonesia, Singapore and Malaysia in a choking haze, raising air pollution to hazardous levels, and forcing schools to close and outdoor events to be cancelled.
The Chinese company identified as a suspect, Palmina, has a concession in Banjar regency. Its president, Chinese national Wang Deming, has been declared a suspect. Three locally owned companies operating in other areas of South Kalimantan province are alleged to have burned several hundreds of hectares of land in total.
Also identified as suspects are top officials at all four firms, who could be jailed up to 10 years if found guilty.
"We are still doing the investigation and making some checks," South Kalimantan police director for special crime, Colonel Nasri, told The Straits Times.
Separately, South Sumatra police are investigating two companies owned by Malaysian investors, Inti Agro and Musi Banyuasin Indah, for allegedly committing the same crimes, according to documents obtained by The Straits Times.
The national police chief, General Badrodin Haiti, on Monday said that his agency was investigating 48 plantation companies and 209 individuals not officially linked to firms for setting illegal forest fires.
A director of South Sumatra-based plantation company Putra Hang Tuah, Mr Petrus Purba, and the company's estate manager, Mr Marwan Tarigan, the estate manager of another plantation company RPP OKI, Mr Paino Setu, and local farmer Edwar have also been declared suspects, the police document says.
The South Sumatra provincial police said they hope to submit the results of their investigations next week to state prosecutors, who will then draw up the indictments and table them to district courts.
Yesterday, Japan joined the emergency firefighting efforts, donating two tonnes of flame retardant to Indonesia.
Indonesian satellites detected more than 750 hot spots on Sumatra as of yesterday.
"It is not easy to put out fires that are burning massively on a vast area of land," said Dr Sutopo, who noted that dry conditions are hampering the efforts.
"New fires have also kept emerging. This explains why the number of hot spots has continued to fluctuate," he said.