why india uses 230 volts
The statistics you found are interesting, but they may not reflect the whole story.
The requirements on insulation are actully more stringent for the 230V system. However, when the switch occurred, the electrical companies and the regulatory bodies made sure that the test voltage was the same, i.e. 2000V, for both 110V and 230V systems. The rationale behind this had nothing to do with safety, but rather with cost: since the existing 110V wires had already been tested at 2000V, tey could remain in place and simply used for 220/230V, without any additional cost of replacing them. Nice how standards are pushed by economic considerations...
Generating DC or AC is pretty much the same, the only real difference is in the generator's commutator. But the real reason why the AC is in use today is because at the turn of the 20-th century the Serb Nikola Tesla, who immigrated to the US, proved that AC was superior, vs. the DC proposed by Thomas Edison.
The great advantage of AC is the ease with which the voltage can be stepped up or down by the use of transformers. Back then this was the only way and it made it possible to transmit power over long distances with relatively low losses by using high voltage. At the consumer's end the voltage is stepped back down. All this with simple transformers which have a relatively high efficieny.
The same was not possible with DC. Anyway, not that easily.
With today's technology, it is possible to step up/ down DC voltages and transmit power efficiently over long distances. In fact, since it is DC, the losses are lower, because even at 60Hz there are some losses in an AC system, due to capacitive loading. This is the drive behind the efforts, by Siemens for instance, to make high-voltage DC systems. Another advantage of a DC system is that the magnetic field, which is thought to have negative effects on humans, is constant, as opposed to changing at 50/ 60Hz.