India has blocked service to all mobile phones without a valid identity code, as part of anti-terrorist measures being implemented by the Indian government.
On Monday, any handset without a valid International Mobile Equipment Identity (Imei) code had its connection cut off, according to the Indian Cellular Association (ICA), which represents mobile operators in the country. The mobile industry is complying with a government directive that arose after discussions between Indian security agencies and the Indian Department of Telecommunications, the ICA added.
The Imei, a 15-digit number printed inside a phone, can be used to identify a particular device on an operator's network, meaning it can be tracked by security services. In addition, network providers can use the absence of an Imei to cut off a phone.
"We have to abide by the requirements of national security, and help to create a legal, ethical market," Pankaj Mohindroo, ICA president, told ZDNet UK on Tuesday. "As an industry, we need to respond to national security concerns."
The ban, which came into effect on Tuesday, is the result of an Indian government directive that became law in October 2008, according to Mohindroo. The implementation of the directive was delayed until March, then June, and finally November, so mobile operators could put in place the technology necessary to block phones with no Imei, an invalid Imei, or an Imei that consists solely of zeroes.
Owners of handsets had until Monday to validate their Imei number or purchase a fresh Imei number. About 13 percent of handsets in India are unbranded Chinese imports, according to a report in The Times of India, and these often have a common Imei.
The number of handsets that had been affected by the blocks was difficult to calculate, said Mohindroo. A BBC report on Tuesday estimated that 25 million phones were affected, but Mohindroo said that due to the complexity and size of the Indian mobile-phone system, the ICA would not estimate.
"The '25 million' number is based on an estimate that five to eight percent of subscribers would be affected," said Mohindroo. "But there are all kinds of numbers floating around. It's impossible to give a number."
Mohindroo said the directive would mean more genuine handsets on the market, and benefits for consumers such as after-sales.