Orangi was one of the biggest slum of ASIA before orangi pilot project......
"The Orangi Pilot Project (OPP) collectively designates three Pakistani Non-governmental organisations working together, having emerged from a socially innovative project carried out in 1980s in the squatter areas of Orangi Town, Karachi, Pakistan. It was initiated by Akhtar Hameed Khan, and involved the local residents solving their own sanitation problems. Innovative methods were used to provide adequate low cost sanitation, health, housing and microfinance facilities.
Currently OPP designates three organisations, borne out of the original OPP in 1989 : OPP-RTI (Research and Training Institute), OPP-OCT (Orangi Charitable Trust, involved in microfinance) and OPP-KHASDA (Karachi Health and Social Development Association, involved in health activities). A fourth organisation, OPP-RDT (Rural Development Trust) was merged with OPP-RTI in 2012."