A very large fraction of our people defecates in the open, on dry riverbeds, on railway tracks, near fields and many a time directly in water.
Untreated human excreta is a health hazard. It may cause water pollution and soil pollution. Both the surface water and groundwater get polluted.
A septic tank is an underground chamber made of concrete, fiberglass or plastic through which domestic wastewater flows for basic treatment.
Settling and anaerobic processes reduce solids and organics, but the treatment efficiency is only moderate. Septic tank systems are a type of simple onsite sewage facility.
Chemical toilet is a toilet that is not connected to a sewage system but has a compartment in which waste is treated with chemicals for temporary storage.
Letting off drainage in rivers will cause water pollution.