According to Trai's 'Independent Drive Test Report' for May, there has been 'general improvement' in the parameters used for measuring the quality of 2G networks in Delhi-NCR.
"However, in case of the call drop rate parameter, further improvement is desired," it said.
Most operators have improved their network performance, Telecom Regulatory Authority of India added.
In most cases of 3G network, the call drop rate has deteriorated in comparison to the previous drive test, the deterioration being highest in case of Idea, it said.
"In summary, the operators -- Airtel, Vodafone, Reliance, Aircel and Idea -- need to further improve the call drop rate performance, the CDMA operators and MTNL need to improve across all parameters, in order to offer acceptable levels of service," the report added.
In Hyderabad, majority of operators failed to meet the call drop rate benchmark of two per cent.
"Out of 14 networks tested, 11 do not meet the required benchmark for call drop rate," it said adding that 3 areas -- Banjara Hills, Secunderabad and Gandhamguda -- out of 10 in Hyderabad contributed to about 60 per cent of total call drops.
However, if the dropped calls are excluded in these areas, all operators in Hyderabad come close to the benchmark of two per cent, it added.
As per the report, Chandigarh is among the better performing cities where most of the operators met the call drop rate parameter with the exception of Airtel 2G, Videocon 2G and BSNL 3G.
"Airtel 2G and Videocon 2G are the only 2 operators who need to improve the quality of the network in Chandigarh," it said.
In Bhopal, Airtel and Vodafone met the call drop rate benchmark in their 2G networks, while Airtel only marginally failed to meet the benchmark in its 3G network.
"All other operators fail to meet the benchmark, by a wide margin.
"Other than Airtel 2G and 3G and Vodafone 2G, every other operator has a call drop rate of over 5 per cent," the report said.
Idea, Reliance and BSNL have call drop rates in the range of 10 per cent or above.
"These are exceptionally high and clearly indicate urgent need for improvement in order to deliver reasonable levels of service," it said adding that it is possible for other operators to offer much better quality of service than is currently being provided.
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