"International" might mean just USA+Canada - that's already two countries, so it's international. And that's how it's written in current Canon EF Lenses Limited Warranty from Canon USA:
The limited warranty set forth below is given ... with respect to the Canon
... Photographic Lens Products ... when purchased and used in the United
States or Canada.
To make sure what terms apply to your lens, refer to the warranty documentation that came with your lens. If it says worldwide, India should be included. If your local service refuses to accept it, try contacting Canon USA to help arranging the service in your country.
Note that Canon has given the warranty to you, the original buyer, not the person you're selling the lens to; if they have data about your ownership, they may refuse to transfer the warranty to the second-hand buyer (who obviously won't be have gotten the lens from an authorized dealer).