Six Indonesia provinces, including three close to Singapore, have declared a state of emergency to battle land and forest fires as the dry season is set to peak this month, officials say.
Three of the provinces hit by the forest fires are in Sumatra - Jambi, Riau and South Sumatra.
The other three are West, South and Central Kalimantan provinces.
There were 433 hot spots across Indonesia detected by satellites on Tuesday morning, with Riau recording the largest number at 132, according to the National Disaster Management Agency (BNPB).
The government has sent nearly 5,700 firefighting teams to douse the fires in the various provinces, and also deployed 33 helicopters, along with two aircraft to seed clouds to induce rainfall.
The latest hot spot figures compare with over 750 hot spots just on Sumatra island alone in mid-October 2015 - at the peak of the national fire crisis, caused by massive burning to clear land for palm oil, paper and rubber plantations.
That year, Singapore, Malaysia and parts of Thailand and Indonesia were covered with choking haze for over a month.
In Riau, often the origin of the dense smoke that spreads to neighbouring countries, BNPB acting spokesman Agus Wibowo said the fires so far are concentrated in small areas and remain under control.
"Our team is working hard to fight fires in Riau. But so far, the concentration (of fires) is still small and therefore, the situation is still safe," he told a news conference yesterday.
The firefighting teams, comprising soldiers, police officers and disaster management officials, are spread in the villages. Dr Agus said helicopters would be called for water-bombing runs whenever a big fire gets too hard to control.
The government has sent 1,262 firefighters to Riau, and 17 helicopters stand ready in Riau, he added.
Dr Agus, referring to the forecast of continuing dry season until September, said: "(The) worse fires will still potentially happen, but with the joint team that works on the land and from the air, we hope we can avert the 2015 incident."
To curb fire starters, at least 16 people have been arrested so far this year, according to BNPB. No incidents involving companies have been reported so far.
Meanwhile, the Riau capital of Pekanbaru was blanketed by haze on Tuesday, but residents were able to conduct their activities as usual and there was no flight disruption from the main airport, according to local media reports.
The haze abated in Pekanbaru yesterday, Mr Jim Gafur, head of emergency response at the Riau disaster management agency, told The Straits Times.
He said the forest fires were from Langgam district in neighbouring Pelalawan regency, 35km away from Pekanbaru.
Firefighters have been deployed while three helicopters water-bombed the area, he said.