Thank you very much.
It's actually a very complicated story, but in fact it's part of their reaction to our presidential election. Our presidential election resulted in the election of the person least welcome by China. They took a series of actions, following our election, to punish Taiwan, and this was one of them. In this unilateral change of the flight routes in the middle of Taiwan Strait, which are already very close to the median line, they now make it even closer, and not only that but there is no southbound. In the Taiwan Strait, there is no southbound route: They actually reactivated another route—M503—in the middle of the Taiwan Strait.
Now, if they fly eastward from the coastal areas to connect to this M503, either to fly northbound or to fly southbound, they are actually coming to the middle of the Taiwan Strait without you being able to discern whether this is a passenger flight or a military warplane. That has already taken half the distance they need to cross the Taiwan Strait, squeezing our air defence zone, so it is very much a national security concern to us.
We brought this up to ICAO. ICAO seems to be unable to find anything to check Chinese behaviour. According to the ICAO regulations, any change of the flight routes should be informed or negotiated priorly with your adjacent FIR—flight information region—and that is Taipei's FIR.