Guests attend the Joint Network and Thematic Meetings of the National Ozone Officers of the 54 African countries in Gaborone, capital of Botswana, on May 21, 2018. The United Nation (UN) Environment, Africa office has applauded Africa's 54 countries for their efforts to phase out CFCs and Halons among others, which were some of the most widely used ozone-depleting substances. (Xinhua/Sharon Tshipa)