Effect when shares written off

An investor is asking if they can claim the purchase cost of Lakshmi Vilas Bank shares, which were written off due to a merger in November 2020, as a loss on their Income Tax Return (ITR) for the financial year 2020-2021. The shares were bought in March 2020. The initial response suggests this is not allowed under the IT Act, as there was no sale transaction, leading to a discussion about the fairness of this rule.