NYT: RIO DE JANEIRO — The problem of the suddenly green water in the Olympic diving pool worsened Wednesday as whatever was ailing the pool migrated (albeit in a lighter shade of green) to the nearby pool used for water polo and synchronized swimming. But Olympic officials said that after extensive tests, they had finally pinpointed the reason: a chemical imbalance caused by too many people using the water.

There had been speculation Tuesday that algae was the cause, but that theory was dismissed by officials.