We were assigned by pairs to a specific NGO.
The NGO I went had as a purpose to keep children away from the streets, they will pick them up after school and give them activities as well as lunch in the evenings.
The NGO did not had many resources and the teachers working were mainly volunteers, however we did our best to teach the children other subjects besides the ones taught at school. We mainly gave music, sports, language lessons.
The most important effect we had in the kids was that they had our attention.