Stone India Ltd is an 80-year-old engineering company that has developed a biological toilet system called Enbiolet as part of its corporate social responsibility efforts. The R&D team spent 35,000 man hours developing Enbiolet, which uses bio-media and bacteria to fully digest human waste into non-toxic water and gas within a multi-chambered tank, eliminating solid waste discharge. Enbiolet has been installed in various locations across India, including at construction sites, urban slums, railway platforms, parks, and schools, providing more hygienic and eco-friendly sanitation where sewage infrastructure is lacking.