Rob de Jong, head of the Air Quality and Mobility Unit at the UN Environment, speaks during Africa Clean Mobility Week Conference at the UN Environment headquarters in Nairobi, Kenya, on March 14, 2018. Executive Director of the UN Environment Erik Solheim on Wednesday called on African governments to put policies and finances in place to start adopting electric vehicles to cut air pollution during Africa Clean Mobility Week Conference. (Xinhua/Lyu Shuai)