Telecom Regulatory Authority of India has issued show cause notices to Bharti Tele, Reliance Infocomm, and Idea Cellular for not adhering to prescribed format for advertising tariffs to consumers.

Trai has given the three companies time till December 1 to reply as to why appropriate action under the relevant provisions of law should not be taken against them for violation, sources said.

Confirming the receipt of the notice, Reliance spokesperson from Mumbai told PTI, "Trai had raised certain issues and we will provide explanation on all those issues."

Bharti denied that the company was served any such notice.