Several important rules pertaining to PAN cards, banking, mutual funds, EPF and other things that affect everyone's life are set to change from April 1, 2019, the starting of the next financial year. The deadline for linking PAN card with Aadhaar is March 31, 2019. If you fail to link your PAN with Aadhaar, your PAN card might become invalid. The Supreme Court in September last year, while declaring the Aadhaar scheme as constitutionally valid, had said Aadhaar was mandatory to file I-T returns and issuance of PAN card.