18 million phones blocked due to double registration, theftPTA has designed a system called Device Identification Registration and Blocking System.It was recently launched to control grey traffic. Around 38 million phones have been blocked so far.Grey trafficking is used to make an international look like a domestic call. It is used for international roaming as it saves money and the identity of the caller is hidden. Grey routes are made outside the arrangements of the licensed telecom companies in the country.PTA is working against grey trafficking because it comes from unlicensed companies and no taxes are paid on these calls. This also works against the registered companies as they lose market shares and eventually part of their revenue.