The number of hot spots picked up across Indonesia by satellites fell slightly to 214 yesterday, said the National Disaster Management Agency (BNPB).
This came after forest fires, most of which were located in the western regions of Aceh and Kalimantan, led to 239 hot spots the day before, said to be the highest this year.
While the haze from fires in West Aceh - which had forced some schools in its capital Meulaboh to close - had largely abated, more hot spots were detected overnight in West Kalimantan and Riau, now the two worst-hit provinces.
Figures The Straits Times received from BNPB spokesman Sutopo Purwo Nugroho yesterday showed 59 hot spots in Riau and 46 in West Kalimantan.
Dr Sutopo had attributed the rise in the number of hot spots to the seasonal dry spell, which is forecast to last until September.
Forest and peatland fires in Sumatra and Kalimantan, that led to the transboundary haze, have been kept at bay since 2015.
The haze caused record air pollution levels in the region for months that year, pushing Indonesia to the verge of a national emergency.
Since then, the central government has been working with the local authorities and plantation companies to ramp up efforts to prevent and fight fires.
But as the dry season kicked in, all eyes were once again on Indonesia following reports that smoke from fires caused dozens of people, including children, in Meulaboh to suffer lung infections from the haze.
Aceh police chief Teguh Priyambodo Nugroho said yesterday that 14 people have been called in for questioning in connection with the forest fires in the regency.
He told Kompas News that these include both land owners and workers who were present at the time of the fires, but they remain witnesses until the police have evidence to prove otherwise.
The schools in Meulaboh reopened yesterday morning as conditions improved throughout most of the country, with air pollution between "good" and "moderate" levels, according to Indonesia's Meteorological, Climatological and Geophysical Agency.
Meanwhile, aerial firefighters in Riau have dropped more than 21 billion litres of water over fires raging across the Indonesian province in Sumatra since January, as efforts to prevent a repeat of the haze crisis continue across the country.
The amount, delivered by helicopters over 549ha of land affected by fires in the province thus far, is enough to fill more than 8,800 Olympic-size swimming pools, or supply Singapore's total water demand for 11 days.
Similar water-bombing missions were also flown in recent days over West Kalimantan, where the highest number of hot spots had been recorded since last Thursday.
Environment and Forestry Minister Siti Nurbaya Bakar said yesterday that these air sorties are focused on fires in areas where there is limited road access. "If land access is difficult or shut down for a long time, then we will use water- bombings," she added.
Neighbours Malaysia and Singapore, which were also badly affected by the haze in 2015, have reiterated their offers to assist Indonesia in its firefighting efforts.
Senior Minister of State for Defence and Foreign Affairs Maliki Osman also reaffirmed Singapore's commitment to work with Indonesia to tackle the haze issue, during his visit to Pekanbaru and Jambi last week.