In a letter of reply to volunteers engaged in trash sorting in a residential community in Shanghai, President Xi Jinping expressed hope that they would continue to play a unique role in grassroots governance and encourage more residents to develop the habit of sorting trash. Two years later, China Daily revisited the community to find out how local residents have made waste sorting a "muscle memory". Professor Marie Harder from Fudan University praised Shanghai's achievement, stating that what a mega city of 25 million people has accomplished in waste sorting is truly remarkable.