Also from the TOI pages - an interview with Sushma Swaraj.

But why is 'mainstream' equated with Mumbai which produces only a third of the 800-plus films made in India every year? What about Tamil, Telugu, Malayalam or Bengali films?

On the contrary, 'art films' imply only cinema in the languages! I wouldn't call it regional cinema, we've a better description in the term 'Indian diversity'. This term embraces different languages, different audiences, different ethos. It's true that Hindi films have a much larger audience and a wider reach. But, to take one instance, Rama Naidu's films are all mainstream. So it'd be wrong to equate mainstream with Bollywood.