Aadhaar number is a 12-digit unique identity number issued by UIDAI

Highlights Aadhaar mandatory for filing income tax return, obtaining PAN

December 31 last date to link Aadhaar card with PAN card

Mobile phone users need to link SIM with Aadhaar by February

1. Deadline for linking Aadhaar with PAN - December 31, 2017

2. Deadline for linking Aadhaar with mobile number (SIM) - February 2018

3. Deadline for submitting Aadhaar details to banks/financial institutions - December 31, 2017

4. Last date to give Aadhaar details to avail social security schemes - December 31, 2017

Linking of Aadhaar has been made mandatory for many essentials. These range from applying for a PAN or Permanent Account Number to filing income tax returns (ITRs) to using a mobile phone connection. All mobile phone numbers or SIMs not linked with Aadhaar will be deactivated after February 2018, according to a report by news agency Indo-Asian News Service (IANS) citing informed sources. The government is moving ahead with linking Aadhaar with mobile SIM cards , the agency added. Many telecom companies have asked their customers to finish the process of linking Aadhaar card with mobile number citing government directive. Aadhaar number or Unique Identity Number or UID, which is printed on the Aadhaar card, is also to be shared with financial institutions and has to be submitted to avail the various social security schemes.Aadhaar is based on biometrics-based data. Aadhaar number is a 12-digit unique identity number issued by the Unique Identification Authority of India (UIDAI). Be it linking of Aadhaar with PAN, mobile SIM cards or bank accounts, there are different deadlines specified in each case.Here are four important deadlines to remember for you to link your Aadhaar with the various documents or products:In August, the Central Board of Direct Taxes (CBDT) extended the last date for linking of Aadhaar with PAN "to facilitate ease of compliance by the taxpayers". The new deadline is December 31 , 2017. Earlier, this deadline was August 31, 2017. Linking Aadhaar-PAN is mandatory for processing of income tax returns (ITRs) for assessment year 2017-18, the income tax department has said."If this linking (PAN-Aadhaar) is skipped, the return could be considered invalid and the person may have to file it again which shall be considered belated and may attract penalty, interest and other consequences like disallowances for losses," says Sandeep Sehgal, director of tax and regulatory at Ashok Maheshwary & Associates LLP.All mobile phone numbers not linked with Aadhaar will be deactivated after February 2018, according to a report by news agency Indo-Asian News Service (IANS) citing sources. That means mobile phone service users will have to link their Aadhaar numbers with SIM cards . Many telecom companies have now started sending alerts to customers about completing the Aadhaar-Mobile number linking process. They had earlier instructed their customers to start the process of linking their Aadhaar card numbers with phone numbers. (The government has made it mandatory for all banks and financial institutions to mention the Aadhaar details of clients in the KYC (Know your Customer) document. A KYC document basically provides all the details that authenticate the identity of a user. People who have taken loans are also required to file their Aadhaar details. If you fail to link it with your bank account by December 31 this year, it may even become inoperable Quoting of Aadhaar is also mandatory for financial transactions of Rs. 50,000 and above, according to a report by news agency Press Trust of India.Aadhaar number has to be provided for all social security schemes by December 31, 2017. In order to avail pension, LPG cylinders or government scholarships, one must provide his or her Aadhaar card details.

Meanwhile, the government also plans to make linking of Aadhaar mandatory for driving licence. "It (Aadhaar-Licence linking) would be done soon to check the menace of multiple licensing," Electronics and IT Minister Ravi Shankar Prasad has said.(With agency inputs)