Zhang Jinliu is a man on a mission. Speeding through the neighborhood streets of Shanghai on his scooter, the 32-year-old courier knows the vital role he is playing as a lifeline for people in lockdown in need of basic food, such as fruit, vegetables and rice, to keep them going until the latest COVID-19 outbreak is brought under control.

Zhang has been at it nonstop since areas west of Shanghai's Huangpu River were placed in lockdown on April 1. He is one of 21 couriers based at online grocery store Dingdong Maicai's Baotun Road distribution center in Huangpu district. The dedicated deliverymen have been starting their shifts at 6:30 am every day since April 1, and regularly work until as late as 11 pm in order to get food out to people locked indoors.

Despite these long hours and frantic conditions, none of the couriers have complained-instead they are resolute and understand the importance the role they are playing in making sure people have enough to eat at a time of crisis.

"We all just want to deliver as many packs as we can, as quickly as we can. We need to ensure those in the closed-loop have enough supplies," said Zhang, who delivered as many as 200 packages in a single day in the past week.

Four of the nine vegetable distribution sites in Huangpu district have been temporarily closed due to the lockdown and a number of couriers have been ordered to stay home. These closures have further increased the pressure on the ones that remain open.

"Fierce internet traffic with people fighting to place orders online has meant that some people don't get a spot, so we need to keep operating longer to keep up with demand," said Pang Xueting, head of the site on Baotun Road.

"Every courier at my site has told me that they won't rest until they've completed all daily orders."

When China Daily visited a vegetable distribution center in Shanghai's Songjiang district on Sunday, Yang Ren'e, 48, was hurriedly packing carrots and cabbages. "The faster I sort, the sooner the goods will be delivered to people who urgently need them," she said.

"When I think about my family and several others waiting for orders, it inspires me to work harder and faster even though I have to work overtime," she added.

Wang Li, who is responsible for data statistics at the center, confirmed the rapid spike in online orders after the outbreak hit the city. "In the past, some people bought vegetables in markets and some people ate outdoors, but now more locked-down consumers are pouring into online grocery platforms," she said. "It's a big challenge for all the workers in this industry."