Aerial photo taken on Nov. 27, 2018 shows a worker loading the powder of straw and waste wood at a biomass fuel producing company in Qingtongxia, northwest China's Ningxia Hui Autonomous Region. As the heating season comes, biomass fuel producing companies in Qingtongxia Township collect straw and waste wood to produce biomass fuel for the neighboring heating companies. (Xinhua/Wang Peng)