All mobile phones in India without an international identity number are being disconnected in a bid to crack down on the security threat they could cause.
The 15-digit International Mobile Equipment Identity (IMEI) number helps trace any handset whether lost or stolen or those needed to be monitored by security agencies.
Under a government order, from today all mobile phone companies must disconnect from their networks any phones that do not have an IMEI number from their networks.
More than 20 million such phones, mainly cheap Chinese models, are thought to exist in India.
The move follows concerns from the government that phones without IMEI numbers are untraceable and could be security threats, especially if used by terrorists.
Using the IMEI number, the handset can be traced even if the user constantly changes his or her mobile operator.