Indian telcos have been instructed by the (Department of Telecommunications) to avoid rolling out 5G near airports. This is because of the potential interference that C-band 5G can cause with the radio altimeters (RAs) present in the aircraft. The telcos have maintained that their C-band 5G operates in spectrum frequencies of 3.3-3.67 GHz while the altimeters operate in 4.2-4.4 GHz, meaning there's sufficient gap to ensure that there's no interference. However, when it comes to passenger safety, the government won't take any chances and thus on the directions of the DoT, the telcos have not been rolling C-band 5G near airports.
One solution for the issue is to replace the current RAs with newer ones that won't face any interference. It would be a large exercise as every airline would have to spend their resources (time and money) to replace the existing RAs. However, the government isn't setting any sort of deadline for the airlines to do this. It is because, according to a Business Standard report, there isn't sufficient data available to suggest that Indian airlines are facing interference issues because of C-band 5G that the telcos are rolling out.
India wants to wait and monitor the USA's experience of replacing the existing RAs to see what the feedback is. Telcos can't install any 5G BTS within 2100 meters from both ends of the runway and 910 meters from the central line of the runway in the C-band. This is definitely going to affect people who live near the airports in cities.
It is worth noting that in the United States (US), the telcos are rolling out C-band 5G in the 3.7-3.98 GHz band, which is actually closer to the frequency that a radio altimeter operates in. But it is not the same case in India. COAI (Cellular Operators Association of India) has suggested to the government that flight simulations be run to check whether there's actually any interference there or not.