Special Provisions
The President may, by public notification, direct that Union/State laws not apply (or apply with modifications) to a major port or aerodrome, or that existing laws cease to apply there (or apply with modifications) from a specified date.
This gives the President flexibility to create special, tailored legal regimes for major ports and airports - reflecting that these are often nationally significant, specialised infrastructure facilities that may need a different regulatory treatment than the ordinary state/local laws that would otherwise apply to that physical location.
This is why a major international airport or port can, in principle, operate under a specially-tailored legal framework distinct from the ordinary state laws that would otherwise apply to that specific location, given the President's power under this article.