The network was down for over 12 hours. The disruption affected around 20 per cent of the company's total subscriber base of around 2.5 million in the city, with users unable to make or receive calls.
Bharti Airtel, the country's largest mobile services provider, has a total subscriber base of 69.4 million users across all circles in the country.
The fire broke out following short-circuit of a power cable and resulted in stalling of the Airtel's services at Lower Parel, Worli, Churchgate and adjoining areas. Users on Airtel network complained of disruption in services since 10 am.
"The entire Mumbai region was not affected, but only certain places near Lower Parel," a company spokesperson said. Bharti Airtel said, "There has been a major fire due to a short circuit in the common power cables belonging to the power supplier in the facility area of the building.
This has resulted in a disruption in power supply to all the occupants, which has impacted our network services in some areas of Mumbai."
"To alleviate our customers' problems, we have proactively made provisions to route our customers' calls and the affected customers, around 20 per cent of our total base, should be able to resume calling in the next few hours," the company added.