India’s giant Tata Group on Monday unveiled a new low-cost water purifier, hoping to do for health what it did for motoring and provide affordable, safe drinking water for millions and cut disease.

The Tata Swach, named after the Hindi for "clean’’, is designed to be used in poor, rural households that have no electricity or running water, using ash from rice milling to filter out bacteria.

The device, which will cost less than 1,000 rupees (21.5 dollars), also uses tiny silver particles to kill harmful germs that can lead to potentially deadly water-borne diseases like diarrhoea, cholera and typhoid.