To most people it comes as a surprise that there are rivers in Mumbai. This has more to do with the misleading official nomenclature than the lack of awareness. The city’s development plans and municipal authorities refer to them as nullahs – literally small water channels, but conveniently interpreted to mean open drains. And that is exactly how they are treated. Sluggish with raw sewage, chemical and other untreated waste, these rivers have been reduced to noxious quagmires.
The city has four rivers – the Oshiwara, or the Jogeshwari, the Dahisar, the Poisar, and the Mithi, or the Mahim. Varying in length from 10 to 12 kilometres, they have their origins in the forested areas around the city. They also serve as tail-water discharges of the freshwater lakes that supply water to the city. In fact, the location for the lakes (which are manmade) was selected based on the presence of the rivers so that overflow from the lakes would be channelled into the rivers and then out to the sea.
The Oshiwara gets filled at Andheri, a suburb that had suffered extensively during the floods. The river originates in the Aarey milk colony. On its 10-km journey through the relatively unspoilt environment of the national park it is a clean stream. A cocktail of industrial pollutants empty into it as it crosses the Oshiwara Industrial Estate and slums and cattle-sheds lining its bank pour in raw sewage.
As the Oshiwara nears the sea there is a small mangrove forest. It is a shadow of its former self, constricted as it is by housing colonies that are literally squeezing it out of a region that it once sprawled across – a process that continues with debris being dumped into the river on a daily basis. In the past three months debris dumping has narrowed the river and created approximately 20 square metres of new land. About 200 metres downstream, a bridge is being constructed on land reclaimed similarly. As always, lack of accountability makes it easier to carry out illegal activities.