Two major Chinese carriers - China Eastern Airlines (CIAH) (CEA) and Xiamen Airlines – announced they cancelled just under 200 flights combined to and from Taiwan due to increasing tensions between China and Taiwan over airspace in the Taiwan Strait. The cancellations came after China failed to gain approval from Taiwan’s authorities for four new additional air routes.

China Eastern Airlines (CIAH) (CEA) said it cancelled 106 round-trip flights and Xiamen Airlines called off at least 70 flights slated for the busy travel period around the Lunar New Year. The holiday, which starts in February, brings an increased travel demand in the region. The flights had been scheduled in addition to the airlines’ regular Taiwan services. Both airlines announced their decisions on their Weibo social media accounts and blamed escalating tensions over airspace in the Taiwan Strait, Bloomberg reports.

Early in January, 2018, China announced it is adding four extra routes to Taiwan – M503, W121, W122, W123. Taiwan stated on January 29, 2018, that the decision was a “unilateral” action and China failed to ask for its approval, contravening what the democratic government in Taipei has said was a 2015 deal to first discuss such flight paths.

The dispute between the two governments has geopolitical implications. Beijing considers Taiwan a province to be reunited with the mainland. Taiwanese President Tsai Ing-wen, who’s ruling Democratic Progressive Party supports independence, views China’s decision to introduce the new routes over the Taiwan Strait as a threat to Taiwan’s sovereignty.

Taiwan claims that the decision is affecting its aviation safety and national security, as the new routes are too close to existing routes that link it to airports on islands that are under Taiwan’s control but lie close to mainland China. The two groups of islands are Kinmen, which sits opposite to the Chinese city of Xiamen, and the Matsu archipelago near Fuzhou. Multiple daily flights connect the islands to mainland Taiwan. Both Xiamen and Fuzhou are busy airports, Reuters reports.

In another report by The New York Times, the new routes are said to come close to airspace used by Taiwanese airliners and military planes. This area is particularly sensitive since China is known to conduct military drills encroaching on Taiwan’s airspace. Taiwan has said its military is prepared to challenge any aircraft that threaten national security. Meanwhile, the two airlines that cancelled the flights will probably suffer significant economic losses.