The number of civilian airplanes permitted to fly in Chinese airspace at any one time has been almost doubled as part of a regulatory overhaul intended to help reduce flight delays, the Financial Times reported. Under new rules introduced on Thursday, the height of each flight layer between 8,900 meters and 12,500m has been halved, increasing the total number of layers from seven to 13. This brings China in line with international standards for vertical separation of aircraft and creates space for nearly twice as many planes. The country's airspace is controlled by the military, which restricts civilian aircraft to narrow flight corridors on strictly prescribed routes. The delays this causes are said to be exacerbated by unsophisticated radar equipment in some places and a shortage of air traffic control staff.