South Korean airlines have decided to downsize the number of routes between Korea and China during the summer peak season, following less-than-expected passenger demand for traveling between the two countries, according to industry sources on Sunday.

National carrier Korean Air said it will stop the operation of routes between Gimpo International Airport and Beijing from Aug. 1 to Oct. 28, while its routes connecting Incheon Airport and Xian will also be suspended from Aug. 9 to Oct. 28.

The nation’s second-largest carrier, Asiana Airlines, also said it has suspended flights on the Incheon-Xian route since Tuesday. The airline is considering reducing flights between Gimpo and Beijing from July 6. The Incheon-Shenzhen route also will be suspended starting July 8. All three routes are set to resume operations on Oct. 28.

The suspension of major flight routes comes as the number of Chinese passengers flying into Korea decreased over the past few years, and demand from Koreans to travel to China has also plunged, amid worsening relations between the two countries.

According to the data from the Ministry of Land, Infrastructure and Transport, the number of passengers flying into Korea from China in the January-May period stood at 1.2 million, which was 60 percent of the number logged during the same period in 2020 at the beginning of the pandemic, at 1.99 million.

The number of Koreans flying to China also decreased, with the proportion of Korean passengers on flights to China falling from 15.5 percent to 5 percent over the past three years.

The dwindling number of Chinese passengers flying into Korea is majorly attributed to China's continued ban on group tourism to Korea.

In February, China resumed the issuance of visas that had been suspended for nearly three years due to the COVID-19 pandemic. However, among countries China allowed for its citizens to travel in groups, South Korea was excluded, along with the United States, Japan, Germany and Australia.

The move has been interpreted as retaliation against the Korean government's decision in February to restrict visa issuance for inbound travelers from China, citing the risk of the spread of COVID-19.