Fire fighters have been battling forest fires in Sumatra, to try and prevent deadly 'haze'. Forest and peatland fires in Riau Province are said to have burned 3,818 hectares of peatland, blanketing the region in smoke, or 'haze'. The fires are typically caused by attempts to clear land for farming, sometimes for palm oil plantations. But with the land below often comprised of peat, which burns, they can rage out of control for months. Local authorities have distributed face masks to residents, while fire fighters have stepped up efforts to combat the fires. In late 2015, the haze, made worse by months of unusually dry weather, blanketed much of southeast Asia for months, causing many fatalities. Since then, Indonesia has stepped up efforts to prevent and contain forest fires.