Actually the time limit for filing the Form 1 for declaring undisclosed income under Income declaration scheme, 2016 has elapsed on 31st January 2020. Hence, you will not be able to disclose the income through that way. What my opinion is to meet the concerned Principal Chief Commissioner or Principal Commissioner and try to explain them the issue. If you get the positive response from them, then go ahead with the procedure prescribed by them. But if you don't get the desired response, then better wait till any notice to be served on you for that income.