Malaysia declared an emergency in a town in Sarawak state on Borneo Island on Friday after air pollution breached the country’s emergency-level threshold linked to fires in neighbouring Indonesia.The Air Pollutant Index in Serian, a small agricultural town of just under 90,000 near the border of Indonesia’s Kalimantan province, surged to 521 on Friday, according to Malaysia’s environment department.Sarawak’s much-larger capital, Kuching, also showed a hazardous reading of 311.Malaysia’s King Sultan Ibrahim Iskandar has consented to the declaration of an emergency in Serian, which would allow more effective measures to be taken, Prime Minister Anwar Ibrahim’s office said in a statement.It didn’t provide details but officials have said a reading above 500 could provide for nonessential work and outdoor activities to be halted. Schools are already shut if the index is above 200.Haze is a recurring seasonal problem in Southeast Asia, where smoke from forest and peat fires in Indonesia can travel across national borders and affect neighbouring Malaysia, Brunei and Singapore.Sarawak has been the worst-hit Malaysian state by the haze, with several areas having hazardous air levels in the past few days.The haze this year has been particularly severe, with elevated fire activity in several provinces in Indonesia, including Kalimantan, and prolonged dry conditions contributing to worsening pollution across parts of Borneo.Satellite data from Indonesia’s Forestry Ministry on Friday detected 717 hot spots nationwide likely caused by forest fires since 1 August. The data showed 103 active hot spots in the past 24 hours alone.Indonesian authorities have deployed firefighting resources and attempted to induce rain.Indonesian police announced Friday that they have arrested 112 people suspected of starting the recent forest and peatland fires in 10 provinces on Sumatra and Borneo islands. The suspects were local farmers accused of deliberately burning land to clear areas at lower cost.Indonesia has also suspended the business licenses of five companies over alleged forest and land fires within their concessions in the Kalimantan province.Pipit Subiyanto, a senior police official at Indonesia’s National Police criminal investigation agency, said authorities are investigating 167 cases involving the deliberate burning of some 4,700 hectares of land across nine provinces.