I've been to both Delhi (more accurately, Gurgaon) and Bangalore on business assignments. I don't mean to sound unfairly harsh, but it's difficult for me to imagine a city that basically feels like it's constantly trying to kill you become a center of startup activity, for the simple reason that once one becomes wealthy enough to invest in startups one would want to leave the city for a better quality of life.
The air quality and pollution problems in Delhi are like nothing I have ever experienced. When I was there (granted, it was exceptionally poor air quality even for Delhi at that time) I could not see the sun at midday due to the smog - I couldn't see more than 100 feet due to the smog. I felt like Blade Runner could have been filmed in Gurgaon - a post apocalyptic world with giant buildings but a dire lack of accessible green space. Even if there were much green space, I couldn't spend much time outside because every breath tasted like acrid metal.
I'm not saying San Francisco and Silicon Valley are some utopias either - they obviously have a slew of social ills (often debated on HN). But I have never realized how much I have taken for granted being able to breath clean air, and I really hope Delhi is able to clean up its pollution problems, but until it does I can't see it becoming a truly globally competitive startup center.