"The service providers merely provide the pipes for the carriage of the calls and cannot be held responsible for such pesky , nuisance calls made by the marketing agencies," GSM lobby group COAI and CDMA operators group AUSPI said in a joint statement.

Trai is well aware that there is no technological facility available which can help the service provider to discern whether the call is from a telemarketer or is an unsolicited commercial communication, it added.

Moreover, there is no way in which the service provider can ensure that the telemarketer has scrubbed the calling list in an appropriate manner before making the call.

"The entire industry is completely discouraged by this regulation since we have been going out of our way and making all possible efforts to put in a system so as to enable the Authority's (Trai's) UCC regulation to be effective," it said.

The telecom regulator had on Monday said that for the first unsolicited communication, a service provider would have to pay a penalty of up to Rs 5,000, which could go up to Rs 20,000 for each subsequent communication.

However, a telemarketer would have to pay a penalty of Rs 500 for the first unsolicited communication, and Rs 1,000 for every subsequent communication. 

The National Do Not Call (NDNC) registry was set up by Trai in 2007 to check unsolicited commercial calls to subscribers.

The telecom operators had taken the initiative to bring in a common four digit number across all networks for registering with the NDNC. Moreover, they had sought to bring about public awareness through advertisements.

"In spite of all the efforts made by service providers to ensure that all telemarketers register, only about 13,600 telemarketers have got themselves registered out of an estimated total of more than 75,000. This is poor compliance by the telemarketers and their concerned institutions that needs to be urgently addressed to protect the consumers and not demotivate the service providers through penalties for actions for which they are not responsible," the statement said.

However, justifying its move, Trai said in a statement on Monday, "The objective is to increase the effectiveness of compliance of these regulations by providing financial disincentive to non-compliant Telecom Service Providers and thereby reducing the nuisance and inconvenience to the subscribers from the unsolicited tele-marketing calls/messages."