The Pollutant Standards Index (PSI) in Central Kalimantan jumped to 1,801 yesterday, leaving firefighting helicopters grounded with the haze too thick for them to carry out water-bombing to put the fires out.
This came as Indonesia's central bank evacuated the families of its staff from Pontianak in West Kalimantan province as haze conditions there too turned hazardous.
Bank Indonesia paid for the families to move to the coast farther north, where sea breezes and air- conditioning reduced the effect of the smoky air, said Mr Dwi Suslamanto, head of the bank's West Kalimantan office, according to Bloomberg News.
In Palangkaraya, the capital of Central Kalimantan, resident Rusliadi Efendi, 48, who works as a security officer at a palm oil company, found the soupy air hard to bear. "When I sit outside for less than five minutes, my eyes get watery. This has not happened before. In previous times, only my nose was affected," he said.
The number of hot spots in Central Kalimantan surged to 492 in the morning yesterday, up from only 150 the previous day. The sharp increase happened as schools in Palangkaraya prepared to reopen today after a three-week closure since Sept 10.
The city has seen a record period of forced school closures this year.
"This is the longest forced holiday period I have ever experienced. I remember in the 1990s, we had a full week's forced holiday (because of the haze)," said Ms Masmunik Tambang, 59, who has been teaching for 35 years.
The PSI (similar to Singapore's index) in Palangkaraya surged to 1,801 at 1pm yesterday, from 300 the previous night. Any measure above 350 is considered hazardous. Central Kalimantan is the worst-hit province during this year's haze season, with the PSI touching a record 2,300 mark late last month.
Light natural rain that fell on Wednesday in the north of the province gave little respite.
Aerial firefighters were hampered by the thick haze yesterday.
"We didn't manage to come through the thick haze in a number of areas. Therefore, we had to return to base," said Air Force First- Lieutenant Budi W., who flew a water-bombing helicopter.
"If hot spot 'A' cannot be approached, we ought to try to find other hot spots nearby and target those instead, so we don't waste fuel," he added.
He was speaking at a morning operational briefing held at the Central Kalimantan governor's office.
A helicopter was deployed to the Sebangau Kuala area in Pulang Pisau regency yesterday morning, while two others were put on standby in Palangkaraya as the targeted areas were too thick with haze for water-bombing to be carried out.
The briefing, led by Army Lieutenant-Colonel Ulysses Sondang, was attended by weather agency officials, a forestry expert, police, health officials and disaster management agency officials.
Land and forest fires have occurred in Indonesia's Sumatra and Kalimantan every year, ahead of the planting season that usually starts in October and November, as farmers and companies opt to clear land by a slash-and-burn method.
This year, Kalimantan has had more fires than Sumatra, which has traditionally seen more planting activities in the previous years.
Palangkaraya-based weather forecaster Roland Binery said stable rain in Kalimantan is likely to start only early next month. Light rain does not last more than an hour, with rainfall of less than 1mm, while stable rain is more than two hours long, with rainfall of more than 5mm.
As for cloud seeding to induce rain, Central Kalimantan currently does not have enough good clouds to seed, according to Mr Roland.
Many of the hot spots are in the southern and south-eastern parts of the province where the peatlands are concentrated. "In the north, fires are more easily doused as it is not peatland there," he said.