Hi,
Shares held are treated as a Capital Asset. In your case ESOP's have been held for more than one year i.e. it is a long term capital asset. Any long term capital asset generates a long term capital loss or long term capital gain.
Long term capital gain/ loss is determined in accordance to the Section 48 of the Income Tax Act, 1961. According to second provisio to section 48, where long term capital gain arises from the transfer of long term capital asset, benefit of indexation shall be available.
Accordingly you can claim the benefit of indexation.
For the tax rates for the calculating the tax liability same needs to be checked.