Fixed line users will have to add a “0” before dialing any mobile number in the country from January 15, the Ministry of Communications said in a statement.

“All Fixed to Mobile calls will be dialed with prefix ‘0’ from 15th January, 2021,” the Centre said. “There will be no change in dialing plan from fixed to fixed, mobile to fixed and mobile to mobile calls.”

An announcement will be played when a fixed line user dials a mobile number without using the prefix “0”. “A total of approximately 2,539 million numbering series is expected to be generated from the above. This will free up sufficient numbering resources for future use,” the Centre’s press release read.

The government also explained that with this, more connections can be added in the future, “which will be beneficial to mobile customers at large”.

India has 10-digit numbering plans, and series for numbers beginning with “0” and “1” are reserved for special purposes. So in theory, about 800 crore numbers are possible due to this. So far, mobile numbers were registered to series starting from “9” and some combinations beginning with “6”, “7”, and “8”, according to The Indian Express.

A total of 115 crore mobile numbers are currently available with these combinations. The “9” series has been completely used, but those starting with other numbers overlap with a few numbering plans provided to fixed line users. Therefore, in an effort to create enough numbering combinations, the prefix has been reintroduced.

In May, the Telecom Regulatory Authority of India had suggested dialling with the prefix “0” for calls going from a landline to a mobile number, according to The Times of India. The regulator, however, had said that the introduction of a prefix for a certain kind of call is not the same as increasing the number of digits in the telephone number.