If any undisclosed income [in the form of investment in capital asset] is declared under Income Declaration Scheme, 2016, then what should be the cost of acquisition of such capital asset?

The fair market value of the asset as on 1st June, 2016 [which has been taken into account for the purpose of said declaration Scheme, 2016] shall be deemed as cost of acquisition of the asset. [This provision is applicable w.e.f. 1-4-2017]