Mumbai’s water woes extend to the inconveniences caused by its scarcity. But for rural India, the problem goes much deeper. While working in the region in 2005, former electrical engineer Suprio Das discovered the presence of arsenic in Kolkata’s groundwater. On further research, he realised the scale of water contamination in rural Bengal. “In 2009, I started thinking about the need for a simple device that could provide clean water at affordable prices,” says Das. And the idea for Zimba was born.

Innovator Suprio Das with Zimba, a device that automatically treats impure water by fortifying it with chlorine. Pic courtesy/Suprio Das