Yulin, Guangxi province, China (CNN) Boss Ning has been running a dog meat restaurant in this southern Chinese city since 1981 and she says business is thriving.

Her customers can feast on crispy dog or dog hot pot, as well as lamb, duck and other meats.

Dog is particularly popular in the region during the sweltering heat of summer and each June locals and visitors gather for a dog meat eating festival, which this year takes place Monday.

"Crispy dogs smell good and taste delicious," she says, declining to give her full name.

Her customers seem happy too:

"Dog meat is a delicacy. It's nourishing," says one man who gave his name as Huang.

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But the festival, which sees some 10,000 dogs served up as meals, has become a battlefront in China's nascent animal rights movement.

Activists say many of the animals are stolen household pets that are then transported thousands of miles crammed into wire cages and denied food and water.

Many arrive at their destination malnourished and diseased, before being slaughtered and served up to customers, they say.

Losing battle?

A new generation of Chinese animal lovers increasingly view dogs as companions.

Of China's estimated 130 million dogs, at least 27 million are urban pets, according to research group Euromonitor.

And there are signs that dog meat is losing its popularity in some places.

Ten years ago, it was common to see dogs being killed for meat in Beijing's suburbs, says Peter Li, at the Humane Society International.

Today, that is something that is rarely seen, he says.

And in Guangzhou, a city well-known for its exotic eating habits, a dog meat restaurant that had been in operation for 51 years recently closed.

This year, dozens of activists and their pet dogs have descended on Yulin. Some plan to hand in a petition to the local authorities demanding an end to the killing of dogs for food.

Others attempted to rescue the animals from the slaughter house. Hao Wei, an animal rights activist who'd traveled hundreds of miles from Xian in northwestern China, said he'd saved five dogs and two cats.

"We bought them at the place where the dogs are being killed," he said, adding that he'd spent up to $32 on each animal.

"I hope the government would pay more attention to food safety."

"The dogs have skin disease and all kinds of other diseases but the butcher says it should be fine once they've been scorched."

The festival is also generating outrage internationally, with celebrities like Ricky Gervais calling for it to be stopped.

It's misleading to call Yulin a Dog Meat Festival. It should be called a Dog Torture Festival. Because that's what it is. #StopYuLin2015 — Ricky Gervais (@rickygervais) June 21, 2015

CNN crew threatened

The clashes between activists and dog meat traders has led to a tense atmosphere at the city's markets where the dogs are traded.

A CNN crew was stopped from filming by security officials and stallholders brandishing mops -- one elderly lady wielded a knife.

The opposition to the dog meat trade is not just from outsiders. Xie Yanli works in a local cafeteria and says she supports the animal rights activists.

"Most of the people who eat it are middle aged men. They eat dogs and drink beer," she said.

"I don't eat dogs, I never did and won't do in the future."

Liu, a college student from the provincial capital Nanning, said it was his first time to visit the festival. He fears it might be shut down year.

"We just wanted to take a look and try things out."

Restaurant owners say the publicity the animal rights activists have brought to the city has, perversely, only been good for business.

"Originally, people from other provinces across the country didn't know about our dog meat delicacy but after our restaurant was shown on TV, they all come and try it out," says Ning, the restaurant owner.

And many in Yulin don't see what the fuss is about.

"Eating dog meat is a regular thing for me. Dog rearing is the same as rearing pigs or chickens, there is no difference," said a man who gave his name as Zhong, who was enjoying dog hot pot with a friend.