KUALA LUMPUR, Malaysia (AP) — Two of China's most storied winter Olympic athletes faced tough questions about Beijing's bid for the 2022 Winter Games — namely about air pollution and a lack of snow.

Gold medalist figure skaters Shen Zue and Zhao Hongbo came out of retirement to win the pairs title in Vancouver in 2010, then retired again. The husband and wife are two of the Beijing bid's ambassadors trying to convince the IOC that the Chinese city should be given hosting rights over Almaty, Kazakhstan.

The vote will be on Friday.

On the sidelines of the IOC executive board meetings Tuesday, the couple was asked about pollution in the Chinese capital and the lack of snow at the mountain venues of Yanqing and Zhangjiakou. Beijing, which hosted the 2008 Olympics, is trying to become the first city to host a summer and winter games.

Shen said many Olympic ski competitions need artificial snow and "that is something that happens at many Winter Games."

"Often it is for the safety of the competitions and the athletes," Zhao added.

Beijing bid official Xu Jicheng, responding to persistent questions about the air quality for competing athletes, said pollution had improved since the 2008 Olympics and that will continue in the lead-up to 2022 if Beijing gets the games.

"We can promise blue skies and white clouds," Xu said at a packed news conference at a downtown hotel.

Other bid officials were asked about corruption surrounding the bid after last week's firing of a senior Chinese sports official.

Xiao Tian was removed as a vice minister of the General Administration of Sport of China. Xiao was placed under investigation for possible corruption in June.

Xiao was also a vice chairman of China's Olympic committee, and last September he was elected as one of three vice presidents of FIBA, the governing body of basketball.

On Tuesday, bid spokesman Wang Hui said "corruption is a common enemy."

"The Chinese government's position is one of zero tolerance, that is also the wish of all Chinese people," Wang added. "These cases are irrelevant for the bid. They (individuals) attended bid committee meetings because we wanted broad support. But they assumed no responsibilities whatsoever."

Also, Kazakh Prime Minister Karim Masssimov arrived in Kuala Lumpur to lead Almaty's delegation.

As the 15 members of the IOC executive board began meeting, they discovered that Boston dropped out of the bidding for the 2024 Olympics.

Beset by poor communication, low public support, and an active opposition group, Boston was cut by the U.S. Olympic Committee. With a Sept. 15 deadline for official submission of candidates, the USOC could turn to Los Angeles as a new bidder.

On other issues, the IOC board:

— recommended formal recognition of South Sudan, a move that would clear the way for the African country to send a team to the Olympics in Rio de Janeiro. The motion is expected to be ratified by the full IOC on Sunday.

— said the host city contract for the 2022 Games will be made public, including new clauses on non-discrimination, labor laws, and other protections.

— cut the service fee for future Summer Olympic bid cities from $650,000 to $250,000.

— agreed to increase funding to the International Paralympic Committee from $6 million to $7.5 million, and increase the number of athletes at the Paralympics from 750 to 850.

— approved the addition of kiteboarding, BMX freestyle, and beach handball for the 2018 Youth Olympics in Buenos Aires.

On Wednesday, the executive board will receive updates on preparations for the Rio Olympics, the 2018 Winter Games in Pyeongchang, South Korea, and the 2020 Olympics in Tokyo.

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AP Sports Writer Stephen Wilson contributed to this report.