SK Group Chairman Chey Tae-won reinforced his commitment to supporting Busan’s bid to host the 2030 World Expo on Thursday, days before the final voting takes place in Paris to choose the host.

Busan, South Korea's second-largest city, is competing against Saudi Arabia’s Riyadh and Italy’s Rome to host the global event.

“When we first jumped into this international race, the prospect of Busan winning the expo bid seemed almost impossible," Chey wrote in an Instagram post, alongside a photo of him in an economy class airplane seat.

"But thanks to the great dedication of the Korean government and Korean firms, we are gaining so fast (as a runner-up) that nobody can be certain who will win in the race."

Chey doubles as the head of the Korea Chamber of Commerce and Industry, and has been leading the corporate efforts to support Busan's bid.

"I, too, am making my last-ditch effort, meeting prime ministers and Cabinet members of countries every day to gain every single vote possible," he added.

To promote Busan's expo bid, Chey arrived in Paris in early November to canvas votes. He flew out again on Nov. 13 to travel to seven countries in the Central and South Americas and Europe -- the major member nations of the Bureau International des Expositions -- to make the last-ditch effort, before returning to Paris on Thursday, according to industry sources.

During the trip, the chaebol chief reportedly flew economy, raising eyebrows. According to KCCI, Chey's campaign trip covered a distance of some 22,000 kilometers.

Chey is expected to join South Korean President Yoon Suk Yeol, who is also in Paris, to rally final support for Busan.

On Nov. 28, the host city of the 2030 World Expo will be decided by a vote during the 173rd Bureau International des Expositions General Assembly in the city.