More than 20 million phones are likely to go on the blink from December 1 because the government has finally decided to pull the plug on phones without an identity number.

Such phones may look fancy, but they lack one very critical feature which can prove to be costly - the absence of International Mobile Equipment Identity (IMEI) number.

This 15 digit number is critical for tracking any handset whether its lost or stolen or needs to be monitored by security agencies.

Now, the government has ordered all mobile companies to disconnect such phones from their networks from December 1.

More than 2 crore phones in the country are without IMEI. Most such phones are manufactured in China and are popular because they are cheap.

The operators after seeking many extensions have no option but to comply this time.

The Central government is worried that phones without IMEI number are untraceable and hence a security threat. It's after all the IMEI number which allows a handset to be traced even though the user may keep changing the mobile operator.

While this may solve the government's problem, the operators are afraid of losing customers and revenue. So they are encouraging the users to get IMEI numbers implanted on their phones. The operators are offering this service for Rs 199.

Even as the operators scramble to get subscribers to change to a phone with IMEI number, millions of users still don't have IMEI phones which means very soon their phones will stop ringing.