I believe the results regarding waste sorting in Shanghai, a megacity with 25 million permanent residents, are incredible, representing a cutting-edge global achievement.

In terms of the amount of food waste collected every day in Shanghai, I don't know any city in the world that can do this. There is not even a small town in the rest of the world that can achieve this.

In addition to the quantity, the food waste collected is of exceptional cleanliness, which allows for biogas generation and compost production.

Also, most residents in Shanghai are very aware of the possibility that their city is providing a lot of opportunities for recycling.

I had conducted a decade-long study in Shanghai, visiting over 100 communities with my students to identify factors that enhance each individual's waste sorting practices.

For example, we even tried colors. If the waste sorting volunteer wears a bright yellow shirt, and the bin is bright yellow, it can have a small effect.

My team presented a report to the Shanghai municipal government on the main findings of our fieldwork in the city, highlighting three key factors: the optimization and easy access of facilities, residents' awareness of waste sorting roles, and a friendly, warmhearted volunteer near the bins to have positive social interactions with the residents, but never do the sorting job for them.

The research findings were incorporated into Shanghai's municipal regulation covering domestic waste management that took effect in July 2019, and I'm very excited that we made a contribution.

One thing quite special about the Shanghai regulation is that it is explicit about the role of each stakeholder. They include the truck drivers, the truck companies, the district government and the local government at community governance level. The importance of a volunteer to be nearby is clear, and the role and job of the resident is clear as well.

Throughout the process of doing research and working with governments of various levels, I felt that Shanghai is a truly ever-learning city. The city government is very alert and proactive to seed ideas and to learn from pilots. It is always checking, listening to feedback, and trying over many years, and then the pilots get bigger. And they are doing this kind of things in advance of upcoming needs. They try to anticipate the needs and start exploring solutions early.

Shanghai is a place where solutions are developed on the ground, and nurtured where they show promise.

I like China, for I find the general environment is very positive for someone who really wants to make a contribution to society. Everywhere in the country, everyone automatically knows they have to work for the betterment of life of all Chinese, above and beyond any personal targets they have.

Also, in China, and particularly in Shanghai, which I firmly believe will go from strength to strength, the government will notice something small but useful, and scale it up. That's an important reason why I really love to be in China and try to do good work in the country.

Marie Harder was talking with Zhou Wenting.