Is Swimming in the Nude in Public Places Acceptable Behavior?

Swimming has become a popular sport for both young and old in China as it doesn't require complicated equipment and it is easy to get access to water. Even in winter, it is common to see people plunging into the icy waters of a river or lake. But when some people do so without any clothing, controversy arises. This winter, in some places in Lanzhou, in northwest China's Gansu Province, such