Reuters Market Eye - The Department of Telecommunications (DoT) ordered Bharti Airtel Ltd
The DoT also has said Bharti must pay a penalty of 3.5 billion rupees, the source said.
A Bharti spokesman did not have immediate comment.
The government last year barred wireless service providers from offering 3G roaming services outside their areas of service, but a court halted the execution of the order.
Mobile companies in India own 3G licenses only for specific areas of the country and often have agreements with other wireless providers to provide roaming services outside of those areas.
Shares of Idea Cellular
(Reporting by Aradhana Aravindan)