Taking a dog across India is entirely possible, but the rules are scattered across railway circulars, airline pages and bus operators who each decide for themselves, and a ticket for you is never a booking for your dog. Most travel-day disasters come from assuming it is. So this page starts with one question, how you’re travelling, and then shows only what applies to that journey.
Everything here is taken from the operators’ own published rules, which are linked at the bottom of the page. They do change, so open the relevant one again before you book. You’ll also need a vet’s fitness certificate for every mode of travel, and the “Find vets” card on this page will help you find one in your city.