"Previously, classification was a little confusing for me, especially when I was traveling to Japan and South Korea, where I had a hard time dealing with my trash." Wu said. "But I have learned many tips about sorting trash today, and I'll be a better traveler in future."

Zhu Weiqing, a publicity officer in Gaojing town, wrote a song about trash sorting and shot a music video that has received thousands of views online.

"There are already many posters and flyers about trash sorting, so we want to be more creative," he said. The song calls on everyone to do their part in protecting the environment in Shanghai.

Earlier this year, the city published textbooks on trash sorting for kindergartens, elementary and middle schools.

Zhang Yong, associate professor of environmental sciences at East China Normal University and an editor of the textbooks, said he has given numerous lectures on trash sorting at schools, companies and institutes since last year.

"I found that adults have more doubts over trash sorting than children. They say it is too difficult to learn and question the classification criteria," he said. "However, children already have a lot of knowledge about trash sorting, and many see it as something they should do naturally, just like brushing their teeth.

"Some children told me that when they go home, they supervise their parents on trash sorting, just like their parents oversee them doing their homework."

Zhang suggested the authorities should provide the public with more feedback on the results and benefits of trash sorting. "People need to see the social benefits arising from their efforts, so that their enthusiasm can be maintained," he added.

Precious land

The 24 million Shanghai residents produce 28,000 metric tons of domestic every day, and the city's major landfill facility at Laogang, which is spread over 30 square kilometers — about the size of Macao — has operated for more than three decades.

"Land in Shanghai is so precious that we have to change our old habit of dumping freely to enable more waste to be recycled and burned instead," Zhang said.

Shanghai is not alone in fighting the battle against trash disposal and changing people's bad habits, as sorting has been accelerated nationwide, according to the Ministry of Housing and Urban-Rural Development.