On Monday, 25 Chinese warplanes flew into Taiwan’s Air Defense Identification Zone (ADIZ), the largest incursion since the island first started reporting such activity in mid-September of last year. 18 J-16 and J-10 fighter jets were among the People’s Liberation Army Air Force (PLAAF) aircraft detected, along with four H-6K bombers. The remainder included a KJ-500 airborne warning and control aircraft and two Y-8 anti-submarine aircraft. Taiwan’s Ministry of Defense stated that it scrambled its own fighter jets and deployed missile systems to monitor the Chinese activity while radio warnings were issued.

Chinese aerial sorties over the Taiwan Strait are nothing new and PLAAF jets have been known to cross the sensitive median line that unofficially separates the island’s airspace from the mainland. What is new this year, however, is the scale and frequency of Chinese activity which has been concentrated in the northern end of the South China Sea near Pratas Island. January saw an increase in sorties from the mainland as the USS Theodore Roosevelt carrier strike group passed through the region and it was reported that PLAAF aircraft conducted mock attack runs on the American vessels.

While Chinese sorties remained relatively constant throughout late February and most of March, the vast majority of them involved one or two aircraft at most. That changed towards the end of last month when the number of PLAAF jets and reconnaissance aircraft flying over the Taiwan Strait increased significantly. Before Monday, 10 or more Chinese warplanes flew into Taiwan’s ADIZ on three occasions in April alone while 20 aircraft breached it on March 26. Last week, the Chinese aircraft carrier Liaoning and its escorts operated to the east of the island at the same time as PLAAF fighter jets crossed into its ADIZ to the west.

The increasing scale of Chinese aerial and naval activity in recent weeks has heightened fears of a military clash in the region, with the Taiwanese-controlled Pratas Island thought to be especially vulnerable due to its isolation, concerns that have also led to the deployment of 500 Taiwanese marines there. China still considers Taiwan a rogue province and has maintained that reunification is inevitable, reserving its right to use all measures to achieve that goal, including military force. Beijing has never ruled out the possibility of invasion and it has continued to acquire the capability to carry out such an operation through the modernization of its military hardware, the construction of aircraft carriers and landing ships, as well as the deployment of new cutting-edge indigenous weapon systems such as the J-20 stealth fighter jet.

*Click below to enlarge (charted by Statista)