Malaysia declared an emergency in a region of its Sarawak state on Borneo island after hazardous haze from fires in neighbouring Indonesia drove air pollution to critical levels, the Prime Minister’s Office said.

The declaration covers the Serian division in Malaysian Borneo and will see 647 schools closed from Monday until at least the end of next week.

King Sultan Ibrahim “has consented to the declaration of emergency throughout Serian Division, Sarawak, following haze conditions that have reached air pollution levels hazardous to public health and safety”, Anwar Ibrahim’s office said in a statement.

The move came after the Sarawak Disaster Management Committee formally requested the declaration when the Air Pollutant Index (API) in Serian breached the critical threshold of 500, peaking at 519 earlier on Friday.

Under Malaysian guidelines, API levels above 300 are classified as hazardous, while readings beyond 500 could trigger consideration of a local emergency.

Authorities launched a three-day cloud-seeding operation on Thursday as smoke from Indonesia’s Kalimantan region blanketed the state, driving up respiratory complaints and triggering a rush for haze-rated masks.

Emergency agencies have alerted residents and begun distributing clean drinking water to affected communities.

The government said the emergency declaration would allow more effective measures to mitigate the impact of the haze, while the Royal Malaysian Air Force continued cloud-seeding operations over key catchment areas to induce rainfall.