BEIJING (Reuters) -Parts of China's southern city of Guangzhou imposed COVID-19 curbs on Wednesday, joining the tech hub of Shenzhen in battling flare-ups, fuelling uncertainty over commerce and daily life in two of the region's most economically vibrant metropolises.
Several of China's biggest cities have stepped up COVID-19 restrictions this week, curtailing the activities of tens of millions of people.
Authorities looking to balance economic needs with the effort to contain every outbreak said the curbs would run for just a few days, although two northern provincial capitals extended them slightly.
China's so-called "dynamic COVID zero" policy makes it an outlier as other countries gradually do away with curbs, despite the cost to the world's second-largest economy, which already faces slower growth.
Capital Economics estimates 41 cities, responsible for 32% of China's GDP, are grappling outbreaks - the highest number since April.
"For now, the resulting disruption appears modest, but the threat of damaging lockdowns is growing," said Julian Evans-Pritchard, senior China economist at the consultancy.
"And even if they are avoided, we expect growth to remain subdued going forward."
Guangzhou, a city of nearly 19 million residents near Hong Kong, reported just five locally transmitted infections for Tuesday but authorities ordered some areas in one district to halt indoor entertainment and restaurant dining until Saturday.
It also ordered most school grades in the district to delay returning for the fall semester and halt any physical sessions already begun, state media said, while bus and subway services were also scaled back.
In Shenzhen, at least four districts with about 9 million residents have ordered closure of entertainment and cultural businesses and halted or reduced restaurant dining for a few days.
The city's district of Yantian locked down until Sunday a few narrower areas, limiting household shopping trips to just one person every two days, and suspending businesses, although allowing restricted operations by firms in essential sectors.
Shenzhen's education authorities postponed the start of the new semester of offline classes for school grades.
Shenzhen urged residents not to leave without necessary reasons in a statement issued late on Wednesday. It did not specify how officials would police the new requirement, but demanded government, Communist party authorities and state-owned firms make sure their employees are not making unnecessary trips outside the city.
Residents who must leave have to show proof of two negative tests within 48 hours, according to the statement.
The combined economic output of Shenzhen and Guangzhou reached 5.89 trillion yuan ($855 billion) last year, or about half the gross domestic product (GDP) of South Korea.
ECONOMY DISRUPTION CONCERNS
The northern city of Shijiazhuang, close to Beijing, the capital, extended by a day beyond an earlier target of Wednesday its work-from-home mandate covering four districts with more than 3 million people.
The northwestern city of Xining, home to about 2.5 million people, extended until Sept. 5 a work-from-home order for employees in key urban areas imposed from Monday, and initially meant to run until Thursday.
China reported 1,675 new domestically transmitted infections for Aug. 30, the National Health Commission said, down from the previous day's 1,717 new local cases.
Most cases were found in the mountainous region of Tibet and the southwestern province of Sichuan.
Chengu, the capital of Sichuan, ordered the closure from Thursday of all office buildings in a district with more than a million residents. That followed the earlier citywide closure of indoor entertainment and cultural locations.
Entry was limited to staff needed to ensure basic functions of those buildings, government officials in Chengdu said, a restriction to last three days for now.
The commercial hub of Shanghai will restrict large gatherings and avoid unnecessary ones, a municipal official said, as two new local infections were reported on Tuesday, one of them in the community.
Large conferences and events requiring extensive travel must be downsized, delayed or moved online whenever possible, Shanghai health official Wu Qianyu told a news briefing.
($1=6.8920 Chinese yuan renminbi)
(Reporting by Roxanne Liu and Ryan Woo; Editing by Richard Pullin, Clarence Fernandez and Emelia Sithole-Matarise)