China has taken the unusual step of reserving swaths of offshore airspace without explanation for a period of 40 days, issuing alerts similar to those used to warn aviation authorities of Chinese military exercises, which typically last no more than a few days. Beijing hasn’t declared any exercises in the area, sparking a new aviation mystery following an unexplained pause in military flights around Taiwan. The airspace reserved in the current alerts is hundreds of miles away from the self-governing island. The alerts are in effect from March 27 through May 6, and haven’t previously been reported. Formally known as “Notice to Air Missions,” or Notams, such designations are intended to inform pilots and aviation authorities of temporary airspace hazards or restrictions.

Full report : Beijing reserves airspace for 40 days, suggesting possible military activity ahead.