The Income Tax Department has begun to send notices to those who made deposits at banks that exceeded Rs 2.5 lakh. Hundreds of notices seeking the source of the money were issued after banks reported cases of “unusual or suspicious volumes of cash deposits” since the Centre’s decision to demonetise Rs 500 and Rs 1,000 notes, PTI reported on Saturday.

“This is part of the vigil that the taxman has deployed to check instances of tax evasion, money laundering and black money,” said the department, which has also heightened its efforts to monitor bullion traders, real estate professionals and suspected hawala operatives to curb the illegal use of the scrapped high-value currency notes.

The notices were issued under a section of the Income Tax Act, which gives the government office the authority to seek information related to possible tax evasion. The department has begun a nationwide inquiry into the matter.

The country has been grappling for cash, and banks and ATMs have seen serpentine queues since November 8 when Prime Minister Narendra Modi announced the Centre’s decision to demonetise Rs 500 and Rs 1,000 notes. On Friday, the Supreme Court observed that the long queues outside banks were a serious problem and could lead to riots.