The ongoing novel coronavirus outbreak might have compelled most people to stay home to reduce their chances of getting infected, but the scene outside the Ningbo Tangtuan store in Shanghai paints a different picture.

Located in the Yu Garden shopping arcade, the time-honored brand which specializes in sweet desserts has been receiving long queues of customers every day since it started selling qingtuan, a green glutinous rice ball that is a popular dessert in spring for Shanghainese and those from the lower reaches of the Yangtze River.

"Despite the viral outbreak, we sold more than 400 pieces of qingtuan on March 2, the first day we started selling this snack," said Li Yaohua, one of the chefs of Ningbo Tangtuan.

"Because of the outbreak, many of our customers this year ordered online instead of coming to the shop in person," he added.

Li expects to sell around 5,000 pieces per day when the Qingming Festival, which falls on April 4 this year, nears. The reason for this is the qingtuan is a must-have offering that people place on the tombs of their ancestors or family members.

Apart from sticky rice, another important ingredient used is mugwort, an aromatic herb that is often used to treat asthma, inflammation and viral infections. The leaves and buds of the mugwort, which are picked right after the arrival of spring, are smashed and turned into a juice that is used to soak the rice dough, thus giving the snack its distinctive green hue.

As the cultivation of mugwort requires moist soil, the plant is mainly grown in the Yangtze River Delta, where the conditions are ideal. The region is also home to many qingtuan producers.

Besides being a delicious snack, the qingtuan also provides an opportunity for families to get together. Li Yuan, who grew up in Anji of Zhejiang province, is one of those who, together with his parents, make the glutinous rice ball from scratch.

Since he was a child, Li has spent most of his spring weekends plucking mugwort and bamboo shoots with his parents. As he currently works as an editor in a publishing house in Beijing, he now freezes the qingtuan before bringing it back to the Chinese capital.

"It's not as fresh as eating it back home, but it will do. I just love the taste and want to retain a sense of nature in the metropolis," said the 30-year-old.