The diving pool at the Olympics has turned green, and nobody knows why

Spectators and competitors were baffled yesterday, but organisers say there is no risk to athletes

The diving pool at the Olympics has turned green, and nobody knows why

Maria Lenk Aquatics Centre | Image: Mike Egerton / PA Wire/Press Association Images

Rivers and lakes across the world are often dyed green for St. Patrick's Day, but it seems Rio are celebrating about 200 days too early.

Spectators and competitors in yesterday's Olympic diving events were greeted by a rather unusual surprise, as the diving pool had changed colour from light blue to a murky green shade.

The cause of the colour change is so far a mystery.

British diver Tom Daley tweeted a picture of the pool, which showed the contrast between the green water with the light blue colour water beside it.

A sports reporter for The Times of London tweeted that a UK diver said she had trouble seeing her dive partner through the murky green water.

Water quality has been a major issue surrounding the Rio Games, but until now the concerns centred around the ocean and lagoons, and not the pools.

Olympic organisers said water tests were carried out and there was no risk to athletes, and the cause of the colour change is under investigation.

Canadian team leader Mitch Geller suspected the cause was algae that multiplied quickly in the day's warm and sunny conditions.

"Everybody was scratching their heads going, 'What's going on?'" he said, "It seemed to get worse over the course of the competition."

"It's not really dangerous. It's not like it's toxic or dirty or any of that. I think that the filter is busted, but I'm not sure," he added.

Additional reporting by IRN