A customer sorts trash at a seafood diner in Shanghai on Sunday. [Photo by Wang Gang/ For China Daily]

Alizee Buysschaert, a Belgian living in Shanghai, has received many messages about trash sorting in the past month.

Buysschaert, founder of Zero Waste Shanghai, a company that provides consultancy and workshops on waste management, said, "Almost everyone I talk with asks me about trash sorting, including my clients, friends, expats and Chinese — from Guangzhou to Beijing. Even last night when I was in a bar, I heard people talking about how they should sort their trash. When I first came to Shanghai in 2014, people were not fully aware of the trash issue and everything went into one bin, but things change so quickly."

She has since bought a trash-sorting educational kit and designed activities for her clients to help educate them.

Trash sorting has become key not only for specialists, such as Buys-schaert, but for all Shanghai residents, through a municipal regulation covering domestic waste management that took effect on Monday.

The regulation, which was voted on and passed by city legislators in January, requires every household and institution to sort their trash into four categories — recyclables, kitchen waste, hazardous waste and residual waste.

A fine of 200 yuan ($30) will be imposed on individuals who do not comply. For errant companies, the fine can rise to as high as 50,000 yuan. A reward initiative was also launched in which people will receive points when they dispose of trash in a designated area and during set times. The points can be used to buy household necessities such as tissues and soap.

On Sina Weibo, the issue of trash sorting has attracted more than 50,000 posts and 70 million views, but enforcement of the regulation has sparked mixed feelings among the public.

Some people praised Shanghai for being a role model in taking the initiative to solve the trash problem in -megacities, while others complained about the inconvenience the regulation has brought to their daily lives, and made jokes about sorting their trash.

One of the most popular jokes goes: "Think about pigs before sorting your trash — things pigs can eat go to kitchen waste, things pigs don't eat are residual waste, things pigs might die from while eating them are hazardous, and things that can be sold for money to buy a pig belong to recyclables."

Xiao Guiyu, deputy director of the Standing Committee of the Shanghai Municipal People's Congress, said, "Although it's a joke, it sums up the principle of trash sorting in a simple way that everyone can understand." As for the complaints about inconvenience, the legislator stressed that the new regulation is a law, and just like traffic regulations, people have to learn to obey it as long as they live in Shanghai.