Moderate to dense smoke plumes were also observed rising from some hotspots in central Sumatra.
In a statement, Singapore’s National Environment Agency (NEA) said the Asean Specialised Meteorological Centre (ASMC), hosted by the Meteorological Service Singapore, has advised the interim Asean Coordinating Centre on the activation of Alert Level 2 for Sumatra.
Alert Level 2 is activated when 150 hotspots or more are detected on two consecutive days, with dry weather conditions persisting and prevailing winds blowing towards other Asean countries.
Alert Level 3 is triggered when 250 hotspots or more detected on two consecutive days.
The NEA has also registered with Indonesia Singapore’s concerns over the sharp increase in the hotspot count.
For the next few days, dry weather conditions are expected to prevail in central and southern Sumatra.