Haile Gebrselassie, Ethiopia, Track and Field

Earlier this year, marathon world-record holder Haile Gebrselassie made international headlines when he withdrew from the Olympic marathon over air-pollution concerns. He’ll compete in the 10,000-meter race instead. An asthmatic runner, he cares a lot about air quality, and environmental protection in general. He’s promoted clean air and conservation as part of the U.N. Environment Program’s “Champion for the Environment” campaign and in a WildAid PSA.