Keeping aside the politics, is it feasible to monitor and sniff data out the sea fiber directly?
Wikipedia says the cable transmits data at 440Gb/s. So I'm assuming they cannot store a large portion of the data for future analysis. Further, since this was carried in a foreign country, they might not have access to a data center, nor they can transmit it back to the home country (it would need bandwidth of another sea cable). And lastly, I'm guessing most of the traffic must be encrypted.
So how are they doing it? If the news is incorrect, it is even possible to do it for anyone with "a device" that be taken to a foreign country in a plane?
0: https://www.msn.com/en-in/news/other/mauritius-snooping-scandal-%E2%80%94-the-moustache-man-from-india-in-the-centre-of-the-storm/ar-AAZVzrB
1: https://en.wikipedia.org/wiki/SAFE_(cable_system)