Politics means the world of government in general:
The vice-president has a long career in politics.
I hate discussing politics with my family because it always turns into an argument.
Sometimes people talk about "office politics" outside the context of government -this means the connections and actions that people inside a company take in order to gain power, forming relationships and manipulating situations to their advantage.
A policy is like a rule. Countries have policies (foreign policy, immigration policy, gun control policy) but schools and companies do, too:
Our policy is that customers can return an item and get a refund within 30 days of their purchase.
My school had strict policies regarding lateness - if you were late more than five times, you got suspended.
Every other day we fancy different hair styles, sometimes straight, perm or wavy. But do you know that these hair treatments use a lot of harsh chemicals which lead to severe hair fall? Regular hair straightening also leads to split ends, and once it starts splitting, you have to continuously chop them to let your hair grow. Try to avoid them as much as possible and start loving your natural tresses.