What is MNP ? . In simple terms, it will allow you to change your service provider and yet keep the same mobile number provided :
You are in the same location ( Telecom's call it circle)
You are a postpaid user
This is hardly significant since postpaid user's are usually loyal to a service provider unless they are not relocating. Number Portability is really helpfull if the numbers are portable across states and locations but this is not the case. Since the first few digits of a mobile number are set to indicate which circle it belongs to. .........So the paranoia about MNP is quite unwarranted.