Egypt has been working on a forestation project called the Serapium Forest since 1998. Designed to support its economy and fight environmental and climate changes, the forest is watered with wastewater that is high in nitrogen and phosphorous. As a result, the trees have grown four times faster than anywhere in Europe, where conditions are more favorable. With the success of this project, Egypt seeks to expand its forestation efforts in order to transform large areas of the Egyptian desert into arable and economically viable areas. The planned evergreen forests will purify the air, combat desertification and help reduce high summer temperatures. The forest expansion in Egypt is part of a larger tree-planting effort dubbed the Great Green Wall, which will span 21 countries and extend from Senegal in West Africa to Djibouti in East Africa.