Beijing is leaning on its Olympic experience in inviting artists worldwide to design mascots for the 2022 Winter Games during the 10th anniversary celebration of its hosting of the 2008 Summer Games on Wednesday.

Despite heavy winds and rain, thousands of sports enthusiasts took part in group exercises at Beijing's Olympic Park to mark the anniversary.

With 2,022 physical fitness participants in attendance, Cai Qi, president of the Beijing 2022 Winter Olympics organizing committee, launched a global competition for designs of the official mascots of the winter sports extravaganza, inviting graphic artists from around the world to help visualize new images for the 2022 event.

The Beijing 2022 organizing committee will keep online submissions open until Oct 31 for any individuals or companies interested. Winning bids are expected to be announced in the second half of 2019 after evaluation, modification and public review.

"We trust that you will produce fun mascots to fascinate people around the globe, and that they can be great examples for winter sports in particular," said Thomas Bach, president of the International Olympic Committee, via a video message.

Brad Copeland, an IOC adviser, encouraged 2022 Winter Games mascot designers to challenge their imaginations as much as possible.

"I would say be wide open, avoid cliches and be your creative best," he said.

Beijing has stepped up its preparations for the Winter Games with all 26 venues, including 11 existing ones from the 2008 Games, to be ready by the end of 2019.

There is also a national campaign underway to involve 300 million people in winter sports activities before the 2022 Games.

The anniversary celebration on Wednesday also marked China's 10th National Fitness Day, which is also considered an intangible Olympic legacy to inspire more and more Chinese to embrace sports and regular exercise as a lifestyle choice.

The National Stadium, better known as the Bird's Nest, will host the opening and closing ceremonies of the 2022 Winter Olympics.

Meanwhile, the National Aquatics Center, also known as the Water Cube, will be transformed to stage curling competitions in 2022.

About 3,500 mass fitness activities and grassroots sporting events will be held at major public venues across the country, involving more than 90 million sports enthusiasts through Sunday, according to the General Administration of Sport of China.

"Today's celebration reminds us of the great success of 2008, which left an extraordinary legacy for China and Beijing," Bach said.

"Today, it is also an opportunity to look ahead to China's next Olympic chapter. Building on the legacy of 2008, the 2022 Winter Olympics will renew the Olympic spirit in China."