Catching the bug

In recent years, China has caught the running bug in a big way.

Last year, more than 1,000 marathons were held in the country, from 22 in 2011. In 2016, the number was 328, while 134 races were held in 2015, according to the Chinese Athletic Association.

Zhu Yong, an associate professor in the Sports Department at Guangdong University of Foreign Studies in Guangdong province, wrote in a study paper that the growing popularity of running has been fueled by the rise of China's middle class and higher disposable incomes.

Stimulated by affluence, middle class people are paying greater attention to their wellbeing and self-esteem, so fitness and recreation have become the nation's new luxuries. Running satisfies their needs because it not only improves the health and tones the physique, but also builds stamina which reflects a strong mentality, Zhu said.

Regular runners, especially those who run outdoors, are highly sensitive to their surroundings so it's little surprise that the running boom has coincided with greater public awareness of environmental problems, she added.

For example, in 2014, when the Beijing Marathon was held on a heavily polluted day, many runners wore face masks as a quiet protest about unclean air.

Photos of them went viral as netizens complained that the event revealed problems when it was supposed to reflect the capital's healthy side.

To tackle the problem, the central government is undertaking a long-term battle against pollution, so sustainable development is now a top priority.

Policies, incentives and other support measures have been implemented to drive the development of renewable energy, and 10 eco-friendly codes of conduct were issued in June to encourage the public to protect the environment.

The measures include choosing reusable shopping bags over plastic bags and sorting household trash before disposing of it.

While plogging has yet to be included in the codes, its adherents have a strong presence and the feedback from both observers and runners has been positive.

"People realize it's a good thing to do, even if they are just standing on the street yelling hao ren, hao ren (good people, good people) at us!" Eisenring, the Swiss runner, said.

Great potential

Many people who have tried plogging said they would recommend the activity to friends and relatives.

Zhang Xuejuan, 28, joined Trash Running China because she thought it was a cool idea, but after collecting a few large bags of trash during each run, she began to wish people would litter less.

As a marketing professional with an environment-related subscriber account on social media, Zhang is determined to promote plogging as heavily as possible.

"This form of running has a very strong direct impact. In fact, one of our runners quit smoking because he found too many cigarette ends on the streets," she said.