t white tiger - I've met you at Marwell zoo, do you spk Siberian? Serially, I'm sure it's to do with the dissolved oxygen/hydrogen in the water. If you freeze distilled water it's a heck of a lot clearer - try it!
And it also tastes funny. I think the bubbles are caused by the dissolved air, chlorine, fluorine and other trace elements present in tap water forming bubbles when the water freezes. I've heard that boiling some distilled water (pure, deionised water) for a considerable time actually evaporates away most of the dissolved air. Freezing this as soon as possible greatly reduces the amount of air that dissolves back into the water, and you get transparent ice.
The cloudyness is due to air comming out of solution as the water cools. If you boil some water for a while (10-15mins) and then freeze it the ice will be much more clear.