Clean air is key to everyone achieving their potential, not just athletes, reigning marathon world record-holder Paula Radcliffe said on Wednesday.

In an interview with UN News, the track and field legend spoke about how air pollution made her ill while training for major races, and what she is doing as a UN Environment Programme (UNEP) Clean Air Advocate and Ambassador, for the International Association of Athletics Federations (IAAF).

An estimated half a billion people around the globe are runners, and Daniel Johnson began by asking Ms Radcliffe if she felt daunted by the sheer scale air pollution, which kills seven million every year.