For example, if I apply for a patent in U.S. will my rights over the intellectual property be held only in the U.S. or I could also claim my rights over an IP in some other nation, like India? Also, do I have to apply for patents in individual nations?
It is a considerable practice to file a PCT application instead of a national patent application as it allows considerable extra time and a more streamlined process to nationalize the patents in party States.
It is also expected that the Unitary Patent PAP-Protocol, a provisional phase will be up and running some time next June as Germany cleared up some constitutional issues and 17-ish Member States’ EU patent will also be possible with a single filing requiring no additional Member State filing.
It is probably going to be a considerable avenue to pursue that one files PCT, then files a national stage U.S. patent and a Unitary Patent for (most of) the EU.
All EU Member States, except for Croatia and Bulgaria, are signatories to the Unitary Patent Convention, and other than the Member States of Cyprus, Czechia, Greece, Hungary, Ireland, Romania and Slovakia all other Member States provided their presidential or royal assent. It still awaits ratification in France, Germany and Italy to come into force, however.
Another unitary patent convention is also in force for curiosity between Lichtenstein and Switzerland — obtaining a patent in one will be a patent in the other as well.