Why is reincarnation so important to Hindus?
Or... why is it such an important part of india??
For the same reason that obeying God is important to Christians. You want to live a nice afterlife, so you try to get to Heaven.
If you live a noble life on Earth, your next life will be better.
Every religion has to have a theory of its own as an answer to the question, what happens after death and what is meaning of life ?. In hinduism death is not the end of life nor life the end in itself.Your atman is part of parmatman. Based on your karma you either are born again or you merge with parmartman ending the cycle of death and birth for ever.Unlike in other religions your dead body do not have to wait millions of years for the day of judgement, when God will decide again based on your deeds, to send you to heaven or hell. The world all over is trying to come in terms with the Hindu view of reincarnation. It is important of India as this concept has been developed in India over centuries and the majority understands it.