New Delhi: Communications Minister Ravi Shankar Prasad on Monday launched an online portal that will facilitate blocking and tracing of stolen or lost mobile phones in Delhi and Mumbai."This system has been developed by CDOT (Centre for Development of Telematics ) under Department of Telecom and will work in collaboration with Delhi Police and Telecom service providers," the minister said in a tweet on Monday.Citizens can register their request on https://ceir.gov.in/ along with the copy of FIR to block the IMEI number of their lost/stolen device. The request ID can be used to track the status of your request and unblock the IMEI number in future.IMEA number is written on a mobile device box or the bill/invoice. It can also be found on the 'Know Your Mobile' app."CEIR acts as a central system for all network Operators to share black listed mobile devices so that devices blacklisted in one network will not work on other networks even if the Subscriber Identity Module (SIM) card in the device is changed," a statement on the portal said.The roll-out of the portal in Delhi will facilitate requests for blocking of stolen or lost mobile phones by customers, and sharing of traceable data with police authorities, a statement said.