Query

Very good question. Let me explain this. Exempt Supply is a broad term. It includes three type of supplies:
a) Nil-rated/ Zero-rated supply - A supply which is taxable under GST law and is having 0% rate of tax.
b) Goods/Services exempted by notification by Government.
c) Non-GST supplies or supplies which are not at all taxable under GST law. For example - Salary etc...

So, wherever you are reading the word "Exempt Supply", it refers to all of the above 3 type of supplies.