Department of Telecom (DoT) has extended the duration of archiving call data and internet usage records of subscribers to two years from one year due to security reasons.

The amendments in the licences were issued on December 21 and extended to other forms of telecom permits on December 22.

"The licensee shall maintain all commercial records/call detail record/exchange detail record/IP detail record with record to the communications exchanged on the network. Such records shall be archived for at least two years for scrutiny by the licensor for security reasons...," the DoT circular said.

Telecom companies may destroy the data stored thereafter if there is no direction from the DoT thereafter.

The circular said that the amendment is necessary in "public interest or in the interest of the security of the state or for the proper conduct of the telegraphs".

The amendment mandates telecom companies to maintain internet data records of subscribers including login and logout details of all subscribers for services provided such as internet access, e-mail, internet telephony services like calls made from mobile applications or wifi calling for at least two years.

Earlier the rules mandated the archive call data and internet usage records for at least 1 year.