Emoriz Cong was particularly unlucky — she only arrived in Wuhan three days ago, to spend time with her family over the Lunar New Year holiday.

Key points: The lockdown in Wuhan has left millions trapped in the city where the virus originated

The lockdown in Wuhan has left millions trapped in the city where the virus originated Some are too scared to leave their homes, likening it to living in a horror movie

Some are too scared to leave their homes, likening it to living in a horror movie Local public transport has been shut down and people are being told to stay inside

Now she does not know when she will be able to return to her home in Beijing.

Wuhan has been put in lockdown to contain the spread of the novel coronavirus ravaging the city, which has so far infected some 850 people with pneumonia-like symptoms and caused 25 deaths.

Seven more cities in China's central Hubei province have also been put into lockdown as of Friday, covering a combined population of 25 million people.

There are growing concerns the flu-like infection might spread rapidly as hundreds of millions of Chinese travel domestically and abroad during the week-long Lunar New Year holiday.

Speaking to the ABC, Ms Cong said her timing could not have been worse — she was en route to Wuhan when health authorities announced a significant development: the virus was contagious and could spread from person-to-person.

"I was on the train back to Wuhan when [the announcement] was live on TV. Before that, we knew it was serious — but we didn't know it was that serious," she said.

Ms Cong said not everyone on the train was wearing masks; luckily, friends had warned her that many stores in Wuhan had already sold out, so she bought multiple packs before leaving Beijing.

Her parents also stocked up on food last week ahead of the Lunar New Year holiday — a smart move, given their local neighbourhood grocery store is now "closed for sterilisation".

Locals have reported long lines and overcrowding at health clinics amid the outbreak. ( Weibo )

"My parents and I haven't stepped out of our home for three days, except for going downstairs to throw out the garbage," she said

'We are more scared than anyone'

Other Wuhan residents have expressed extreme fear about the situation — writing on social media they feel trapped inside the outbreak's ground zero.

Efforts are being made to sterilise the city, especially around hospitals and health clinics. ( AP: Dake Kang )

"I found the transportation in Wuhan was completely blocked down, I am getting more and more scared," one local wrote on Weibo, China's version of Twitter.

"I have never been this scared in my life. No-one could understand it if you are not right here right now.

"We don't even have public transportation now. We are more scared than anyone."

Others stuck in the city said they had mixed feelings: while they wanted to go home to their families elsewhere in China for the Spring Festival, they did not want to put their loved ones in danger.

Space to play or pause, M to mute, left and right arrows to seek, up and down arrows for volume. Watch Duration: 1 minute 47 seconds 1 m 47 s The ABC's China correspondent Bill Birtles reports from on the ground in Wuhan.

"I returned my ticket and decided to stay at my rental place for [the] holiday," Weibo user Kikyo wrote.

"I was filled with regret, loneliness, and couldn't fall asleep — but when I saw the lockdown notice, I believed I made the right decision.

"I hope people in Wuhan can understand, this is our responsibility, and it is a choice of love not to endanger our family and friends."

Bigger than the Big Apple

While it's certainly not China's largest, Wuhan is an enormous city by global standards. ( Wikimedia Commons )

The sprawling metropolis of Wuhan is home to more than 11 million people: a population significantly larger than that of other more well-known cities like New York City and London.

As the capital of the central Chinese province of Hubei, it is a major transport hub, especially during the Lunar New Year period when millions of trips are made, as people rush across the country visiting their hometowns for the holiday.

The city has three railway stations with lines servicing major cities including the capital Beijing, an airport offering both domestic and international flights, as well as water transport links and inter-city bus services.

But all of these links have been shut down indefinitely as part of the travel ban: even local bus and subway services within the city are being suspended.

That has left Wuhan natives like Bruce Lu, who works in Beijing but travelled back home for the Lunar New Year, in a state of limbo.

He is currently in the nearby city of Yichang visiting his grandfather, but he has no way of getting out — the only train line back to Beijing passes through Wuhan, and he has no idea when he will be able to return to his job.

Train services in Wuhan have been shut off in order to limit the spread of the virus. ( Chinatopix via AP )

"There are only very few flights to Beijing and that's very expensive," he told the ABC.

"Many Beijing companies have notified their staff [that] they will have to be quarantined for 14 days before going back to work.

'Actors in a new Resident Evil movie'

Expats and foreign students in Wuhan have been struggling to come to terms with the health emergency, relying on updates from their respective consulates and embassies, who have told them to stay off the streets.

Papua New Guinean student Ancilla Delai said she is worried about the transmission between people because of how populated Wuhan is. ( Supplied: Ancilla Delai )

Papua New Guinean student Ancilla Delai told the ABC the situation was "very tense", especially after the shutdown came into effect this morning.

"The streets are empty, there's no-one — people are indoors, and the advice is to be indoors," she said.

"I am worried because the transmission was human-to-human, which was already confirmed, and that's the scary part because Wuhan is a really populated place.

"We're doing everything we can do to keep ourselves safe and stay indoors as much as possible because it is really not safe to go out and we can't risk it."

Daniel Pekarek, a student from the Czech Republic studying at Wuhan University, said the situation was like being in the movie Resident Evil: the film depicts a fictional city's attempt to contain a virus that turns people into zombies.

"RIP, we are actors in a new Resident Evil movie now," he wrote on Facebook.

Speaking to the ABC, he said he was not sure about what to do next, but was still trying to get out of the city despite the lockdown.

An empty and deserted street in Wuhan, after the heavily populated city went into lockdown. ( Supplied: Ancilla Delai )

"Many people left with the last train today, [my] only option is to find someone to drive me out with a car," Mr Pekarek said.

"I could've gone to my country but I wanted to stay here as I really do enjoy it, even though all this is happening.

"I always wanted to go to Asia as a kid, and I love it here."