I was only there for about a day & a half and killing some time before we cuaght a connecting flight down to the South.
honestly you could taste the pollution. No idea what it's like at tha time in the morning as I got drunk & slept in till noon the night I stayed over there. Me personally, while I might be able to adapt to teh heat, I doubt Id' be able to run with the smog - even someone having bonfire on my run route is enough to have me gasping.
This was 5 years ago though & I was a stones throw from the airport. Bombay (mumbai) may well have cleaned up it's air a little, it could be fine AM or better quality a little further out.
If you're going to go, a pre / fake tan is not a bad idea - being less white makes it look like you haven't just stepped off the plane & you're less likely to fall for some tourist trap.
I'm glad you're goign - I'm hope I'm not painting a negative picture. I really loved India when I went - it took a little while to adapt or maybe even toughen up - seeing extreme poverty can be a little hard at first. On the other hand everyone was friendly & I felt safe going out there at night