The call drop rate should not be more than 2 per cent and for worst affected cells it should not be more than 3 per cent.
Telecom Regulatory Authority of India (Trai) said the performance has deteriorated during the quarter on sequential basis with regard to worst affected mobile sites or cells having more than 3 per cent call drop rate.
Trai said worst affected cells call drop rate increased to 24.59 per cent during the April-June period from 12.50 per cent in January-March period for 2G services whereas for 3G services, the call drop rate increased to 16.13 per cent from 15.96 per cent in the preceding quarter.
However, the overall call drop rate remained at 1.64 per cent for the reported quarter.
As per Trai parameters, the call drop rate should not be more than 2 per cent and for worst affected cells it should not be more than 3 per cent.
The operators, which are not meeting the call drop benchmark for 2G and 3G services include Aircel, BSNL and Tata Teleservices.
Trai said the gross revenue for telecom operators decreased 0.30 per cent for April-June quarter to Rs 65,030 crore (Rs 650.30 billion) from Rs 65,227 crore (Rs 652.27 billion) in the preceding quarter.
The adjusted gross revenue (AGR) though increased 4.38 per cent to Rs 47,134 crore (Rs 471.34 billion) for the reported period compared with Rs 45,158 crore (Rs 451.58 billion) in the preceding period.
The regulator said monthly average revenue per user (ARPU) for GSM services stood at Rs 126 while for CDMA, it was Rs 107.
The number of telephone subscribers in increased from 99.64 crore (996.4 million) at the end of March to 100.69 crore (1 billion) at the end of June, registering a growth of 1.05 per cent over the previous quarter.
"Total number of Internet subscribers has increased from 30.23 crore (302.3 million) at the end of March to 31.94 crore at the end of June, registering a quarterly growth rate of 5.65 per cent," Trai said.
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