Districts in Shanghai which achieve zero community transmission at first will allow their residents to move around in limited areas, local authorities announced on Wednesday as the city's daily COVID-19 infection numbers maintained their downward trend.

A limited number of residents will be allowed to conduct minimal activities in restricted areas in those districts, according to Zhao Dandan, deputy director of the Shanghai Health Commission.

Three suburban districts in Shanghai – Jinshan, Chongming and Songjiang – were the first to announce zero community transmission since April 20.

Residents in other districts will remain under coronavirus prevention measures, including "static management, massive screening, overall epidemiological investigation and wide disinfection", Zhao told the city's daily COVID-19 press briefing on Wednesday.

"We've made phased achievements, but the situation remains tough and complicated," he said, describing the city's current COVID-19 prevention work as "arduous climbing".

Shanghai's daily COVID-19 infection numbers have been declining for two days, amid the ongoing campaign to achieve zero community transmission across the city.

The city reported 13,562 infections on Tuesday, 20 percent fewer than on Monday. Of these, only 171 were found during community polymerase chain reaction (PCR) screening, down 21 percent from Monday.

No community transmission was reported in six districts on Tuesday – downtown Huangpu and Yangpu as well as suburban Jiading, Qingpu, Fengxian and Chongming.

Altogether, Shanghai has reported 535,600 local COVID-19 cases since the first case in the resurgence was reported on March 1. Among them, some 91 percent are asymptomatic cases, Zhao pointed out.

Shanghai reported 48 COVID-19 deaths on Tuesday – four fewer than Monday – bringing the total since the resurgence began to 238, he said.

The average age of Tuesday's fatalities was 80.85 years. All had severe underlying conditions. Only one of them had been vaccinated.

Of the COVID-19 patients, 244 have severe symptoms and 27 are in critical condition, a 5 percent decline over the previous day.

Meanwhile, a record of 33,173 COVID-19 patients were discharged from local designated and makeshift hospitals on Tuesday after recovering, more than double the number on Monday.

Zhao noted that all local makeshift hospitals have been equipped with common medicines for chronic diseases such as hypertension and diabetes. Doctors will also give prescriptions or transfer those requiring further treatment on their underlying diseases to designated hospitals.

To consolidate the fruits from the ongoing campaign, Shanghai will launch a new round of nucleic acid plus antigen screening through Saturday and will adjust its locked-down, controlled and precautionary areas based on the results, he stated.

More than 51 million PCR tests have been conducted among Shanghai residents in the last five days, with the positive rate gradually declining, Zhao revealed.

Over 100,000 sample collection staff have been working at nearly 20,000 sites for the massive PCR screening. The city can now conduct five million-plus tubes of PCR test samples every day.