Malaysia has declared a state of emergency in a district in Sarawak state after haze caused by wildfires in neighbouring Indonesia increased air pollution to “hazardous” levels.

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”, Prime Minister Anwar Ibrahim’s office said in a statement on Thursday.

 declaration followed a formal request from the Sarawak Disaster Management Committee after the region’s Air Pollutant Index reached levels warranting consideration of a local emergency.

Under the order, 647 schools in Serian will close from Monday until at least the end of next week, alongside government and private offices, plantations, construction sites and quarries, with only essential services continuing to operate.

The state’s disaster management authorities said a three-day cloud-seeding operation launched on Thursday would be extended to at least Monday, citing forecasts of “more conducive cloud formations” during that period.

Sarawak State Disaster Management Committee chairman Douglas Uggah Embas, speaking at a news conference in Kuching, stressed that the emergency applied only to Serian, not the entire state, but urged residents there to take the situation seriously.

“Please minimise outdoor activities and avoid strenuous activities outdoors,” he said.

Sarawak, in the northern part of Borneo island, has been heavily affected by haze for weeks, as have the neighbouring states of Sabah and Peninsular Malaysia.