With the recent outbreak of pneumonia due to the new coronavirus, Wuhan city, the epicenter of the outbreak in China, has decided to cut off its public transportation system starting at 10 AM on January 23rd local time.

You don't need to add city after Wuhan. Your title already informs the reader that Wuhan is a city.

This unusual measure ishas been taken to restrict the public’s transportation to contain the spread of infection.

Most of your entry is in present perfect tense, so this sentence should allow follow that pattern.

The World Health Organization conveyned at a meeting at the Headquarters in Geneva in the afternoon of 22nd January 22nd, local time, regarding the new coronavirus, and have decided to further discuss preventive measures throughout the 23rd.

There should only be a comma before and if the following line is a complete sentence.

Correct Example: I am hungry, and I will make pancakes for breakfast.
Incorrect Example: I am hungry, and will make pancakes for breakfast.

According to the Chinese state media, Wuhan City will be shutting off intercity busses, and subways, as well as closing down railway stations and airports.

Civilians are banned from leaving the city unless it is “under special circumstances”. The release of a.” A seal-off is to be announced. Wuhan City is a metropolis with a population of over 10 million people. ¶
¶
The death toll from the new coronavirus reached 17 people as of Wednesday. So far, coronavirus has infected more than 500 people including patients in China, Japan, the U.S., South Korea, Thailand and Taiwan. ¶
¶
The World Health Organization discussed whether to announce a global health emergency regarding the epidemic of the new coronavirus at an emergency meeting held on 22nd January. However, they postponed their decision for further discussion on 23rd.

It sounds a bit awkward to say "release of a seal-off." Instead, you can just say that a seal-off will be announced.

With the recent outbreak of pneumonia due to the new coronavirus, Wuhan city, the epicenter of the outbreak in China, has decided to cut off its public transportation system starting at 10 AM local time on January 23rd local time.

This unusual measure is being taken to restrict the public’s transportation in order to contain the spread of infection.

More natural: "This unusual measure to restrict the public's movements is being taken in the hope of preventing further spread of the infection."

The World Health Organization conveyned a meeting about the Hnew coronavirus at its headquarters in Geneva ion the afternoon of 22nd January local time regarding the new coronavirus22nd, and haves decided to further discuss preventive measures throughout the 23rd.

According to the Chinese state media, Wuhan City will be shutting off intercity busses, and subways, as well as closing down railway stations and airports.

Civilians are banned from leaving the city unlessexcept “under special circumstances”. The release of a seal-off isA quarantine(?) is expected to be announced. Wuhan City is a metropolis with a population of over 10 million people. ¶
The death toll ofrom the new coronavirus reached 17 people as of Wednesday. So far, the coronavirus has infected more than 500 people, including patients in China, Japan, the U.S., South Korea, Thailand, and Taiwan. ¶
The World Health Organization, at an emergency meeting held on January 22nd, discussed whether to announce a global health emergency regardinglated to the epidemic of the new coronavirus at an emergency meeting held on 22nd January. However, they postponed their decision forpending further discussion on the 23rd.