Constructed wetlands can effectively treat municipal wastewater in developing countries. A pilot wetland in India showed good removal of pollutants like BOD, COD, TSS, nitrates, and phosphates. Mathematical models were used to predict system behavior, with a k-C* model fitting well to the data. The system is cost-effective, environmentally friendly, and has motivated city authorities to implement decentralized treatment wetlands. Wetlands are a low-cost eco-technology for wastewater treatment, especially in tropical countries like India.