China has reserved five areas of airspace off its northeast coast for 40 days, from March 27 to May 6, without explaining why.

Such restrictions are typically linked to military drills, but no exercises have been announced, and drills by the People’s Liberation Army usually last only a few days.

The restricted zones, issued as aviation notices called Notams, span about 340 miles from the Yellow Sea to the East China Sea near Shanghai.

The airspace applies to all activity, even space trajectories, overlapping with the timing of NASA’s Artemis II mission, The Telegraph has reported.

Experts suggest the move could allow China to practice military operations, possibly related to a potential Taiwan conflict.