Tapiwa Chiwewe: You don't have to be an expert to solve big problems

Driving in Johannesburg one day, Tapiwa Chiwewe noticed an enormous cloud of air pollution hanging over the city. He was curious and concerned but not an environmental expert — so he did some research and discovered that nearly 14 percent of all deaths worldwide in 2012 were caused by household and ambient air pollution. With this knowledge and an urge to do something about it, Chiwewe and his colleagues developed a platform that uncovers trends in pollution and helps city planners make better decisions. "Sometimes just one fresh perspective, one new skill set, can make the conditions right for something remarkable to happen," Chiwewe says. "But you need to be bold enough to try."