Modi government's high-voltage drive to go after the big evaders has improved its tax kitty this year, forcing the filing of at least 1.7 crore in extra returns that took its mop-up close to Rs 26,500 crore till December.Finance minister Arun Jaitley in a reply to Parliament said that the tax department had been identifying non-filers by tracking in-house information and tallying it with data on high-value transactions received from external agencies along with TDS and tax collected at source ( TCS )."The mechanism for collection and verification of financial information has been broadened to include data in respect of various types of high-value transactions from banks and financial institutions and high-value expenditure from commercial establishments in the form of Statement of Financial Transaction (SFT)," the FM said, adding that the scope of TDS and TCS was also expanded.He said quoting Permanent Account Number (PAN) was now mandatory for transactions of over Rs 2 lakh, including on property, shares, bonds, insurance and foreign travel. This was yielding enormous data, which was being mined by the tax department.As a result, last year, as many as 35 lakh non-filers were identified, who the tax department believe had a tax liability. Although the number is down from 67 lakh a year ago, many who had large cash deposits may have filed returns.The move is part of an exercise aimed at deepening the income tax system with the FM saying this year, the target was to get 1.25 crore new return filers.He said that after identifying the non-filers, the government was using rule-based algorithms to classify cases into various categories and monitoring them. Text messages and emails were also sent to the targeted groups to file returns and a compliance management cell had been set up to track responses. This was followed by notices.The system is now proposed to be made more stringent through a new mechanism, called Project Insight, to target individuals and seek voluntary compliance.