The government has hit out at telecom operators for not investing enough in networks which in turn leads to call drops. Talking to reporters in New Delhi yesterday, Telecom Secretary Rakesh Garg said that if expenditure on spectrum is set aside, operators have invested only about 13 per cent of their revenue into infrastructure. He rejected the operators' reasons, such as shutting down of towers and radiation fears, for call drops. <br/><br/>The Secretary said, all these factors existed earlier too but the problem has worsened in the last seven months. He said, the operators have not taken adequate action by which this problem could have been resolved. Telecom operators had, on Monday, met the DoT secretary over the call drops issue and demanded a nation-wide mobile tower policy as well as easing restriction on erection of sites for improving quality of telephony services.