According to draft show cause notice, prepared by DoT for legal vetting, Airtel camouflaged caller identities for making promotional calls to non-Airtel mobile customers. DoT is likely to seek legal opinion for issuing a show cause notice to Airtel on charges of hiding caller identity in Madhya Pradesh service area in January, 2011 posing a security threat, Reports PTI.

Earlier in October, 2011, the DoT had imposed Rs 50 crore fine on Airtel. Later in 2012, telecom tribunal TDSAT quashed the penalty saying that Airtel was not issued any show cause notice and hence the order did not comply with principles of natural justice.

According to sources, there has been a delay in issuing notice to Bharti Airtel BSE 0.12 % in the matter. The wing assigned this task has sought legal opinion on whether it is feasible to issue the notice at this juncture.

Airtel did not offer any comment on DoT charges The mobile operator had earlier said that error was made by third party, a call centre. The DoT, however, has said the call centre is not a third party and it serves to Airtel.