SINGAPORE: Ongoing fires in Indonesia that have blanketed parts of Southeast Asia with toxic haze have triggered the highest-level alert by the regional bloc’s climate and fire monitor.

“Activation of Alert Level 3 for the Southern ASEAN region,” the Singapore ASEAN Specialized Meteorological Center said on its website, seen on Saturday.

Based near Singapore’s Changi Airport, the ASMC uses a four-tiered alert level system, from zero to three, with the highest triggered if there is a “high risk of severe transboundary haze in the region.”

This included significant and persistent hotspot activities with widespread moderate to dense smoke haze, observed over two or more consecutive days, dry weather persisting and wind continuing to blow haze toward neighboring ASEAN countries.

The ASMC alert was issued Friday, but similar alerts have already been handed out twice this year — on August 26 and March 27.

The months-long spell of haze has been disrupting life in large parts of Southeast Asia, closing schools and spiking respiratory complaints.

Singapore said on Friday it would issue warnings to seven companies in Indonesia it identified as responsible for fires but warned the worst may yet to come.