A rap about food shortages has become a hit in Shanghai, with the artists behind the song describing it as an attempt to “cheer up” tens of millions of residents locked down in China’s largest city amid a surging Covid outbreak and increasing restrictions.

The song, Grocery Shopping, laments empty shelves and fights in the supermarket aisles, and is set to footage of residents crowding around market stalls, or lining up for PCR tests.

“Set your alarm, wake up, food fight,” the lyrics say. “Order that tofu, but the sauce all gone.”

The song’s release comes as Shanghai authorities expanded some lockdown measures and the city reported record daily case numbers in an outbreak city-wide frustrations.

China is in the midst of its worst outbreak of the pandemic, driven by the highly transmissible Omicron variant. Shanghai is recording the bulk of cases, with the city’s outbreak yet to peak. It reported 5,656 asymptomatic cases and 326 symptomatic cases for Tuesday, up from 4,381 new asymptomatic cases and 96 new cases with symptoms for the prior day.

In response the city has been divided in two, with four day lockdowns and mass testing drives beginning on Monday for one half, and Friday for the other. However late on Tuesday, authorities announced lockdown measures in some areas of the currently free section.

The south-west district of Minhang announced public transportation would be suspended until 5 April, and residents in some western districts received notice from their housing committees that they would be stopped from leaving their compounds for the next seven days.

“We express our deepest thanks to all residents! We will resume normal life soon, but in the next period of time we ask everyone to adhere closely to pandemic control measures, do not gather, and reduce movements,” said one notice seen by Reuters.

Social media messages also circulated that areas of Puxi would be locked down from Wednesday, a claim dismissed by authorities as “rumour”.

For weeks Shanghai authorities were vociferously rejecting rumours there were plans for lockdowns, arresting at least two people for spreading wrong information. Then on Sunday, plans sharply reversed with the announcement of split lockdowns for the city of 26 million people.

Shanghai residents have expressed growing frustration with the measures imposed on the city, particularly food shortages in supermarkets. Residents have reported rising costs for fresh produce, with jokes in groupchats about the empty supermarket shelves soon forcing them to eat the community shrubbery. Elderly people have reported struggling with the technology required for online ordering.

Amid the restrictions and shortages the rap, released on Monday by artists named CATI2, PJ, and Keyso, has become a hit in the city. The Shanghai lyricists sing about food fights, people waking up early to order food only to find ingredients sold out and delivery drivers all busy. In another section PJ describes escaping one lockdown to get trapped in another.

“Thinking it was an excellent idea to use music to cheer up the people of Shanghai and dispel the negative atmosphere online, the three of us got started immediately,” PJ told Sixth Tone.

“We chose buying vegetables as the theme, because it is the challenge that sums this outbreak up the most. I’ve been to the supermarket to stock up on food many times, and each time I saw people pick the shelves clean. It was even worse than when they buy up groceries before New Year.”

There is growing discontent with China’s zero-Covid policies and the subsequent lockdowns across cities and provinces as Omicron challenges China’s usual methods of containing outbreaks. Coupled with the fear among officials of punishment for failures, harsh and hasty measures have in some cases proved distressing, even fatal.

In a repeat of January’s lockdown in Xi’an, where at least one man died and a woman miscarried after they were denied entry to hospital, refusal of medical care is again causing concern in Shanghai.

Media reports have described dialysis patients – who receive life-preserving treatment about three times a week – denied entry to multiple hospitals. Last week a nurse in Shanghai died after she was denied entry to hospitals after suffering an asthma attack. Such refusals go against government policy, which has only requested hospitals suspend general outpatient services.