Complex sentence: While the alumni travelers were in Soweto, an urban area in the city of Johannesburg in Gauteng South Africa, they participated in the tree planting program Alumni Holiday International (AHI) that was developed 3 years ago.
Split into simpler sentences: While the alumni travelers were in Soweto, an urban area in the city of Johannesburg in Gauteng South Africa, they participated in the tree planting program. The program is called Alumni Holiday International (AHI), and it was developed 3 years ago.