 For example, the Mudially Fishermen's Cooperative Society is a collective of 300 families that lease 70 hectares into which wastewater from the city is released.Through a series of natural treatment processes – including the use of Eichhornia crassipes and other plants for absorbing oil, grease and heavy metals – the Cooperative has turned the area into a thriving fish farm and nature park.Recently illegal landfills are on the rise and the wetlands are being slowly assimilated in the stream city.