blue swimming pools

Why are swimming pools usually blue?

Had someone put coloring in the water? Was their TV set broken?

Eventually some answers came. There had been a change in alkalinity in the water, said one official. Another blamed algae.

The green diving pool at Maria Lenk Aquatics Centre next to another that is the usual color - although that too later turned green

Meanwhile, FINA, the international governing body for swimming, said the water tanks had run out of water-cleaning chemicals.

With so many different answers, it's about as clear as the water in the murky pools.