The right solution is to leave it to parents and students to decide what languages they want to study in and what languages they choose to learn.
Hindi is gradually becoming universally understood all over the country precisely because it was not imposed on linguistic minorities. When people don't feel that their culture is threatened they are open to learning Hindi. Bollywood and television has done more to promote Hindi than all the academic language bigots making decisions from Delhi.
I am sorry but I have to disagree with you here. What you are saying isn't happening universally and I am a witness to it myself. I am from Karnataka (Kannadiga) and I can travel around Karnataka and speak in Hindi or English and I am not discriminated against. Heck people here speak Tamil as well to those Tamilians who do not know Kannada.
However, I travelled to Trichy, Kumbakonam and Chennai and the atmosphere is sadly totally opposite to what you claim. Unless you know Tamil no one is going to respond positively. My driver (who doesn't speak Tamil) had trouble asking for directions as the locals knew that he was not a Tamilian and guided him incorrectly. Only after I involved was I able to get the correct directions.
I noticed the same issue in Kerala when I visited Palakkad and Guruvayur (Thrissur). Unless you know Malayalam it is really hard to find your way around. You speak Hindi and you get a stare down so English is the only way to converse. And let me tell you, these are people who know Hindi and other languages. They just don't want to speak it.
These are anecdotes and may not be reflective of the entire state but nevertheless left a really bad taste in my mouth. I never experienced this sort of discrimination anywhere else in the Country (and I have travelled a lot). And that says a lot coming from a South Indian!
Hindi is gradually becoming universally understood all over the country precisely because it was not imposed on linguistic minorities. When people don't feel that their culture is threatened they are open to learning Hindi. Bollywood and television has done more to promote Hindi than all the academic language bigots making decisions from Delhi.