What I am saying is that in my experience, foreign nationals without immersive exposure to English tend to speak heavily accented, many times to the point of unintelligibility, English. Perhaps your Indian colleague has a gift for languages or actually has been immersed in an English-speaking environment long enough to "lose" much of his accent. Perhaps as he was learning English he had a teacher who was particularly attentive and/or knowledgable about how English is spoken and sounds. I don't know. I'm happy that you find working and communicating with him easy.
I worked a help desk at one time (small company with sophisticated software, not a lot of customers - maybe 20 or 30 - but priced high enough and with maintenance fees for support), and always dreaded calls from one particular site. The guy was from Malaysia and spoke so thickly accented that it was *very* hard to understand.
Time went by, and his enunciation improved. Eventually, the company made him an offer and he came to work for us. More time passed, the company president retired, and he himself became the president of the company. By that time, he still had an accent but while it was noticable it was no worse than, say, most British English speakers.
One of the guys up the command chain from me is from Asia (Korea, I think); he also speaks with a slight but noticable accent. But he's perfectly understandable.
So don't think I'm painting all people from Asia or any other part of the world with a "I can't understand the hell what they're saying" brush. Some, through schooling, immersive language training, or some other means, speak English very well. It's just that I am somewhat less than confident Dell or whatever company they hire will take the care to ensure that their offshore help desks will be so - after all, this *is* a cost cutting measure, and the more costs cut, the better.