Canada-based Indian filmmaker Deepa Mehta might have wielded the megaphone for serious movies like "Earth", "Fire", "Water" and "Heaven On Earth" but she says whatever be her subjects, they derive out of her "passion" for good stories.

"I don't make commercial films or work in Bollywood. I don't have a book with formulas. It (a film) just happens on what touches me. It's a story, " Mehta told.

"It takes two years of my life to make a film. I am not an actor who makes films every four months. So it better be something that I am passionate about. Otherwise what's the point?" she added.

Mehta's next is the big-screen adaptation of Salman Rushdie' bestseller "Midnight's Children".