The network of Bharti Airtel - one of the country's major telecom service providers - collapsed in the Capital, especially in the central and eastern parts of the city, for several hours on Thursday evening.
The company did not come out with any specific reason for the network failure. Even customer helpline numbers failed to elicit any response.
But an engineer with another major service provider said, "This could be due to software problems in the network or failure of some of the main switches."
This caused great inconvenience to Airtel subscribers in the Delhi circle. According to the Telecom Regulatory Authority of India's data, Bharti had 7.98 million subscribers in the Capital at the end of March 31, 2011.
"I was not able to contact my family when I left office at 5.30pm," said Vinay, who goes only by his first name.
Girish Dabral, a sales manager in a private firm, said, "I was supposed to call my colleagues who were in the field, but I could not contact them from any of the telephone connections that we have in our office."
After the service resumed, an Airtel spokesperson, however, said around 10.20pm: "An unforeseen technical outage affected services in some of our circuits. As a result, some of Airtel Delhi mobile subscribers have experienced connectivity issues. We deeply regret the inconvenience."