Consequences of not filling air in itr-2

I had purchased immoveable property of of high value and fails to disclose the same in my annual return in Schedule-AIR of ITR-2 and the same mistake i committed since last 3-4 years continually.

Kindly let me know the consequences of the same and also suggest remedy available.

Now department caught my all records. Altough i had never booked any income being all transactions were of purchase not of sale.   

Kindly expedite your suggestion.