Most Mumbai cabs, old Fiats (is that repetitive?), have some sort of text or graphics on their windows. This guy had the OM symbol centered on his rear window. The text mentions his guru's name and possibly his name - Sandip.
The smaller auto rickshaws seen in previous posts (tuk tuks in SE asia - golf carts in the west!) are allowed only in the suburbs. Cabs can go throughout the city/suburbs but are a bit more expensive and have a reputation for being 'cheats' compared to rickshaw drivers (drive you around in circles or the long way because you don't know where you are - yes, this has happened to me!).