The finance ministry's crackdown on tax evaders has begun with over 35,000 nonfilers , who had made significant transactions, sent I-T notices to substantiate their source ofincome and why they had not filed their tax returns. 

Notices were sent after the intelligence wing of the Income Tax Department's Directorate of Criminal Investigation sifted through more than 4.7 crore financial transactions , accessed through banks and Financial Intelligence Unit. Of the transactions analyzed by the I-T department, more than 12 lakh entities with valid PAN numbers have been identified who did not file their returns.

The government, struggling to meet its tax target , had last year started abusiness intelligence project to identify PAN holders, who have not filed their returns and about whom specific information was available with various financial institutions and with the government's own revenue intelligence agencies. 

Revenue secretary Sumit Bose had on December 10, 2012 warned non-filers to disclose their income as the government was considering initiating action against those who were suppressing their income and evading taxes. "In the first batch, letters are being sent to 35,170 PAN holders by the Directorate of Intelligence and Criminal Investigation," a finance ministry press note said on Monday.

The notices sent to non-filers contain a summary of the information of their transactions along with a customized response sheet and reasons why they had missed filing returns. 

The press note said a nodal cell has been set up in the I-T department to go through the response and take follow-up action . "There will be an online monitoring system to ensure follow-up action and track return filing and tax payment of the target segment," the note said. The business intelligence project to identify non-filers is being executed by the I-T department's directorate of systems .

The information has been collated through the Annual Information Returns (AIRs) filed by financial institutions and banks and the I-T department's own data collection through tax deducted at source. Information in the cash transaction reports of FIU has also been included as part of this data matching exercise.