Official forecasts called for rainfall of 250-280mm in some areas of southeastern Jiangsu province, Shanghai, and northeastern Zhejiang
Authorities in Shanghai and neighbouring coastal regions cancelled flights, and suspended schools, subways, and trains as Typhoon Chanthu approached China after drenching Taiwan though causing little damage there.
The storm, with winds of more than 170kmph near its eye, had been downgraded from a super typhoon to a strong typhoon on Sunday evening and was expected to gradually weaken, Shanghai city authorities said in a post on their official WeChat account.
But it was still expected to bring strong winds and heavy rain to coastal regions.
The province of Zhejiang near Shanghai raised its emergency response to the highest level on Sunday, closing schools and suspending flights and rail services in some cities, the official Xinhua news service reported.
Zhejiang also issued red alerts for flash floods in nine districts. Ningbo port, China's second-biggest container transporting hub after Shanghai, had suspended operations since Sunday noon.
The port just resumed from weeks-long port congestion, following typhoon In-Fa in late July and a Covid-19-related terminal closure in mid-August.
In Shanghai, home to about 26 million people, all flights at the city's larger Pudong International Airport were to be cancelled from 11am local time (0300 GMT), while flights from the smaller Hongqiao airport in the west of the city were to be cancelled from 3pm, the Shanghai government announced on WeChat.
Port terminals in Shanghai regions suspended containers import and export services from Monday till further notice.
The city also suspended subway services on some lines serving the city's southern districts, and said parks, outdoor tourist attractions, and playgrounds would be closed on Monday and Tuesday. Classes were also due to be suspended on Monday afternoon and Tuesday.
Official forecasts called for rainfall of 250-280mm in some areas of southeastern Jiangsu province, Shanghai, and northeastern Zhejiang.
The typhoon passed by Taiwan's east coast over the weekend, disrupting transport and causing some power outages, but otherwise little damage.