Wildfires in Indonesia are driving air pollution in the region to critical levels. Smoke is smothering the nation and sending choking haze to neighbours Malaysia, Singapore and the Philippines. Malaysia has declared a state of emergency in Serian, a district near Indonesia's Kalimantan region that has the highest number of hotspots. The air pollutant Index there has surged beyond 500 — far above the 300 threshold considered hazardous. Melissa Goh reports from Kuala Lumpur and Chandni Vatvani reports from Jakarta.