As the world prepares for the start of the Olympic Games in Paris, it is still unclear whether the city’s iconic Seine River will be clean enough for competitive swimming events.

Yale’s Jordan Peccia and Vasilis Vasiliou discuss the pollutions risks that caused officials to ban swimming in the river more than a century ago, the investments made by French leaders to bring the Seine to safe swimming standards, and the weatherrelated factors that might still prevent open water swimming events during the Paris Games.

And they discuss why the situation is relevant to communities worldwide dealing with public health threats due to water pollution.

Peccia is Thomas E. Golden, Jr. Professor and Chair of Chemical & Environmental Engineering at Yale School of Engineering & Applied Science. Vasiliou is the Susan Dwight Bliss Professor of Epidemiology and chair of the Department of Environmental Health Sciences at the Yale School of Public Health