When you redeem the corpus from index funds, your capital gain will be taxed. If you hold an investment for up to 1 year, then the capital gain on your corpus will be called short-term capital gain and taxed @ 15%. However, if your holding period is more than 1 year than the gains are called long-term capital gain and gain over Rs 1 Lakh is taxed @ 10% without providing the benefits of indexation.