It's sort of a fixed expression. It is used quite often so it may be useful to remember it:
What is that colour/smell/language?, What kind of colour/smell/language is it? = Co to za kolor/zapach/język?
Jellei is right. You can also use this phrase talking about present:
Co za mecz! Co za dzień! = What a match! What a day! (note the lack of jest or to in this case)
This phrase is quite universal. Similarily to English, you can say Co za mecz! referring to the match you've watched before, you are watching right now, or you heard about it and you think it's going to be awesome. In fact it's the best way to translate that What a...! phrase.
I would add another usage: co to był za mecz! (what a game it was!) - expressing how awesome something was.
Can "Co to był tamten hałas?" be also correct ?If I do understand the below mentioned explanations, "za" has a value of exclamation and could imply "too much noise". In this possible in this context to use "zbyt" instead of "za" and write "Co to był zbyt hałas?"... Thank you for your answer.
No, none of those is a correct sentence, I'm afraid. And no, it's not that 'za' implies too much noise here... ok, "hałas" by definition is loud, but the construction itself doesn't imply that. That's a different meaning of 'za', just used in this construction.
It is more like Geradd explained it "...co za..." would mean something like "what a...", "what kind of..."