NEW DELHI: Massive searches, seizures and surveys by the Income Tax (I-T) department over the last three years have led to the detection of around Rs 71,941 crore of "undisclosed income", the Centre has told the Supreme Court.During the period of demonetisation from November 9 last year to January 10 this year, "The total undisclosed income admitted was more than Rs 5,400 crore" and the total quantity of gold seized stood at 303.367 kgs, the Finance Ministry has said in an affidavit to the apex court.It gave the details of the unaccounted income for three years from April 1, 2014 to February 28 this year, including the demonetisation period.The affidavit said that during the three year period, searches were undertaken by the IT department in over 2,027 groups "which led to the admission of undisclosed income of more than Rs 36,051 crore"."This is in addition to the seizure of undisclosed assets worth Rs 2,890 crore," it said.Similarly between April 1, 2014 to February 28 this year, the IT department conducted more than 15,000 surveys which led to "the detection of undisclosed income of more than Rs 33,000 crore".Highlighting the achievements of the demonetisation period, the affidavit said in about two months from November 9 last year, "significantly large number of enforcement actions were undertaken by the IT Department"."They included 1,100 searches and surveys and more than 5,100 verifications. The total seizure through these actions was of about Rs 610 crore, including cashof Rs 513 crore. The cash seizure included seizures in new currency of more than Rs 110 crore. The total undisclosed income admitted was more than Rs 5,400 crore," it said.The Finance Ministry, which recently refused the demand to give more grace period for depositing the scrapped Rs 500 and Rs 1,000 notes, said the Ministry of Home Affairs in its July 11 communication has reported that as per intelligence agencies, there were reports of largescale misuse of the window for exchange of the demonetised currency notes."Seizure of cash during the month of November and December 2016 was to the tune of Rs 147.9 crore and Rs 306.897 crore and seizure of gold for the month of November and December 2016 was 69.1 kg and 234.267 kg respectively," it said.It said that over 400 cases were referred to the CBI and the Enforcement Directorate (ED) after several instances of manipulation for conversion of unaccounted cash held in specified bank notes into legal tender by various entities was detected during the investigation.