Telcos have sought parity with over-the-top (OTT) players that provide communications services such as WhatsApp and Skype, saying these apps provide similar services such as voice calling and should be brought under the same regulation as carriers. "It is an undisputed fact that VoIP (voice over Internet protocol) service offered by OCSPs (OTT communication service providers) is a substitute for" services offered by telecom service providers (TSPs), Rajan Mathews, director general at GSM industry body Cellular Operators Association of India (COAI), said in a letter to the telecom regulator dated June 3.

"OCSPs offer these services without holding any licence in India, which is violative of the Indian Telegraph Act. The licensing and regulatory regime cannot allow a situation wherein the licensed entity (read: Telcos ) is treated at a lower footing than an unlicensed entity (read: OCSP)," COAI said.

At the heart of the matter is the fact that communication apps offer calling services at far lower rates than carriers — mostly a consumer just pays for the data consumed — thus eating into the telcos' revenue pie. Voice still accounts for around 80% of a telco's revenue.

Telcos want these apps to be brought under regulation, so that the apps need to pay the same levies such as licence fee, spectrum charges, etc. Besides also following rules around security, lawful interception, quality of service.

Experts say this could mean the apps wouldn't be able to offer calling and messaging services virtually for free because of the increased costs. Communication apps say any move to regulate them will stifle innovation. Besides, they say, consumers anyways pay data charges for using the OTT platform on a telco's network.

Mobile phone operators had made similar demands during the debate over net neutrality in April 2015.

TRAI is "also aware of the fact that cheaper voice services of OCSPs is merely the outcome of economic and regulatory arbitrage between PSTN voice telephony offered by TSPs and Internet telephony/VoIP provided by OCSPs,"