THE appearance of Gang Segina 6, an alleyway in West Denpasar, Bali, has changed. Gone is the awful stench of the residents’ septic tank effluent that seeped along the narrow path. “Now it feels we’re living healthier,” said Andi Maryono, 41, a member of the Segina Asri Community Sanitation Group, recently.

Formerly, the neighborhood—consisting of about 200 families—was classified as pakumis, an abbreviation of padat, kumuh, miskin (