Govt is setting up a Registry of IMEI Numbers – a Central System where all Operators will be able to share data on Stolen/Lost phones. 
Central Equipment Identify Register (CEIR) will be started with BSNL in Pune as pilot project for 6 month, before pan India Rollout.
Under CEIR, operators will share lists of Stolen/Lost Phone, making sure that a phone on one’s network does not get activated on the other.
Many Western countries like UK already CEIR Imei database. Even shared among many European countries. Though it’s voluntary for operator there still most operators supports it.
How it works in west?
User reports to their mobile operator about the theft with FIR n original invoice. Thereafter the mobile devices’s IMEI number is entered into the CEIR. Now all other operators makes the device unusable in their network.
Like if we place request of lost phone with Airtel expect it won’t work on all the operators that supports the list like Bsnl/Idea/Jio etc.
Though we have many shops who can change IMEI(illegal) all together still it involves lot of work and is not for every device. Like most apple device won’t support imei change.
So more likely your misplaced phone be returned when this get active.