The government has prohibited imports of all kind of mobile handsets with fake or duplicate unique identity numbers, a move that will help security agencies in tracking callers using different SIM cards.

"GSM mobile handsets with duplicate IMEI or fake IMEI & 'CDMA mobile handsets' with duplicate ESN (Electronic Serial Number)/MEID (Mobile Equipment Identifier) or fake ESN/MEID are added to the list of 'Prohibited' items for import," Director General of Foreign Trade said in a notification.

An IMEI (International Mobile Equipment Identity) number-a 15-17 digit number unique to mobile phones that use the global system for mobile communications (GSM) technology platform-is used to identify a device on a cellphone network.

The unique number helps in tracking mobile phones. The move aims to check proliferation of mobile handsets with duplicate or cloned IMEI numbers, which are dangerous for national security.

While there is already an order in place which bans import of mobile phones with fake, without or with '00..00' IMEI numbers, the new order places bans on duplicate handsets as well.

"We welcome any crackdown in fake IMEI or grey market. The implementation of this notification on gorund will have to be handled with great care so that ease of business is not hampered while curbing grey market," Indian Cellular Association National President Pankaj Mohindroo said.

Mobile phones without the unique security code are making inroads into the grey market by cloning the IMEI numbers of genuine sets. Duplicates phone have further added to woes of customers, companies as well as security agencies.