Massive wildfires burning across Indonesia's Kalimantan (the Indonesian portion of Borneo island) and Sumatra have scorched nearly 94,000 hectares in July alone, sending toxic haze across borders into Malaysia, Brunei, and Singapore — with Kuala Lumpur briefly ranked the world's most polluted city. Emergency rooms in West Kalimantan have seen roughly 5,000 respiratory patients per week since July, up tenfold from earlier in the year, while hundreds of schools in Malaysia's Sarawak state have closed. Authorities blame a combination of land-clearing fires set by plantation companies and an intensifying El Niño weather cycle expected to peak in September, with experts warning conditions may worsen further before seasonal rains arrive in November.