India's Tata Group is famous for launching the the world's cheapest car, the Nano compact. Now the company is taking on the challenge of providing clean drinking water to the 894 million people worldwide who lack access to it. The Tata Swach (Hindi for "clean") doesn't require electricity or running water. And at less than $21 a pop, the device is purportedly the cheapest water filter in existence.
Tata's filter, which lasts 200 days for an average family of five, uses a combination of paddy husk ash and tiny silver particles to kill 80% of all bacteria that cause waterborne disease. The company can afford to produce the Swach on the cheap because India produces 20 million tons of paddy husk ash each year as a byproduct of rice milling.
Tata plans on launching the filter first at a plant in West Bengal. Initially, the company will produce 1 million units a year, with 3 million units each year expected to be produced within 5 years. India will have first dibs on the product—a big market considering 85% of the country drinks unfiltered water—but ultimately Tata hopes to export the filter to Africa.