Even for India, this blackout must have a huge impact. (
Even for India, because power cuts are way of life there, with most consumers getting power only part of the day. Major metropolises publish schedules for power cuts, as in 'no power in these areas 3pm to 9pm, Mon - Wed, ...' ).
Yes, twice the population of the US impacted. Even individually, the numbers can boggle the mind : I cannot imagine the state of travelers in the 300 odd trains that were stranded on the tracks at various places (maybe some still are), each with 1000-2000 passengers for more than half a million left to fend for themselves in this heat, away from home or even railway stations

. Hospitals are generally equipped with generators, but this might be more than they could have planned for.
Maybe some good will come out of this. Infrastructure - or lack thereof - has been the bane of India. But just the advent of cell-phones has seen a dramatic shift around in the telecommunication scene in the last few years, maybe this will be the last straw for the electricity arena; there are good examples with certain states managing electricity better than others. WSJ covers it
here.