Telecom operators will need to shut down 5G services in high-frequency bands in and around airports following restrictions imposed by the Department of Telecom at the request of the civil aviation ministry, according to sources.

Based on buffer and safety zone details provided by the aviation ministry, the DoT has asked telecom operators to not install 5G base stations in the 3.3-3.6 Ghz band in the area of 2.1 kilometres from both ends of the runway and 910 meters from the centre line of the runway of Indian airports with immediate effect.

"Telecom operators will need to shut down 5G service in the 3.3-3.6 Ghz band only in and around airports based on the order. It is a temporary restriction. The services can be restored after DGCA (Directorate General of Civil Aviation) ensures that altimeters at all aircraft have been replaced. DGCA has not shared any timeline for completing the replacement exercise," a source told PTI.

Airtel is the only telecom operator that has installed 5G services at select airports, including at Patna, Bengaluru, Pune, Varanasi and Nagpur.

The DoT notice dated November 29 has asked telecom operators to tilt down 5G base stations to avoid interference of 5G signals with that of altimeters-- a device which helps pilots maintain the desired height of the aircraft.

The DoT in the notice said that DGCA is expected to complete the altimeter replacement exercise in a proactive and time-bound manner.

DoT has requested DGCA to provide a timeline for replacement of radio altimeters and its filters with a sharp cut-off date.

"Further, DGCA should communicate geo-coordinates of four corners of all the airstrips where such limitations or restrictions are required to be placed on 5G systems, within 30 days from issue of this letter," the notice dated November 29 said.