If believe on the orders of Department of Telecommunicatin (DoT), 13 digits mobile number can be issued for SIM based machine-to-machine services, which will co-exist with 10-digit numbers. DoT already has issued the direction to all telecom service providers to start issuing 13-digit digit numbers for SIM based machine-to-machine (M2M) services, which will co-exist with 10-digit numbers. These services may start from 01st July 2018.
M2M services means services involving internet-enabled devices like point-of-sale machines (PoS) or even latest refrigerators that communicate through a SIM card. This decision will not have any effect on existing mobile phone SIMs.