Question

On what basis and how will you determine whether air is saturated with vapor or not?

Answer 1

On the basis of amount of water vapours present in the air, it can be either saturated or unsaturated. If the amount of water vapours exceeds the amount that the air can contain, then it is called saturated. If the amount of water vapour is less than the limit of the amount that air can contain then it is called unsaturated.
We can determine whether the air is saturated with vapour or not in terms of relative humidity. If the relative humidity is $100$%, the air will be saturated otherwise not.