Clear bottles do not indicate an inferior product, but the darker bottle will help to prevent your olive oil from going rancid. Amber and green bottles help to block UV rays, which can deteriorate olive oil over time, making it go bad.
Article source: https://feeds.feedblitz.com/~/632137178/0/usatoday-lifetopstories~How-to-know-if-youre-buying-good-olive-oil/