To answer your question, it can be a pressing fault, dust, dirt or scratches.
It's quite hard to understand vinyl sometimes, and a completely flawless looking record can sound awful, and in this case, it can only be something in the manufacturing stage that is causing the problem. There are times when a good clean can get rid of some, or most of the background noise, clicks and pops, but there a no guarantees, though it's always worth a try. I've also got some records from my much younger years, when I didn't take any care of my records at all, and they play much much better than they look.
TSP is right about a lot of newer pressings, but there are plenty of cases of vinyl back in the day being pretty poor. I have a copy of Spiritualized - Live At The Albert Hall, and it's a completely awful pressing, clicks, pops, background crackles, the lot, and it looks immaculate, but on the whole, I prefer an original or earlier pressing to a newer one.
I would say, if you buy a new pressing, and it's less than perfect, take it back and exchange it, and keep doing that until either you get a good one, or you give up and get a refund.
When vinyl is good, it's unbeatable, but it can be a frustrating format.