Kibera slum, the largest and most populous slum in Africa, is located on the edge of downtown Nairobi in Kenya. The population there is between 700,000 and 1 million. Since there is no sanitation service in the slum's three square kilometers, garbage produced cannot be processed, making it a community on a garbage mountain.

In the past year, several students at the University of Nairobi launched the “Green Kibera” project, organizing people to clean up the garbage, classify it, obtain government support, and transport the waste to landfills. Volunteers known as the "Little Green Men" wear green long trousers. There are also Chinese volunteers. CGTN takes you there to see how garbage is sorted in Africa.