Learn Spanish (Latin America): No puedo manejar por la niebla.

Por translates to "because of" or "due to" when it is followed by a noun, like la niebla (the fog). You would use porque (because) if you were following it with a complete phrase that has a conjugated verb, for example: No puedo manejar porque hay niebla (I can't drive because there is fog).

Could por la niebla also mean "through the fog"?

Yes! Por can indicate both a reason ("because of") and movement ("through"). Without extra context, manejar por la niebla could mean "drive through the fog." However, saying "I cannot drive through the fog" and "I cannot drive because of the fog" have a very similar practical meaning in this situation.

I have learned conducir for "to drive". Why use manejar here?

In Latin America, manejar is the standard and most common word for driving a vehicle. You will mostly hear conducir used in Spain. Both are correct, but for Latin American Spanish, manejar is the word you will hear most often.

Why does manejar stay in its infinitive form instead of being conjugated?