One of his most difficult rescues last year, he says, involved two cats that had fallen into a building's ventilation shaft, where they remained trapped for three days. He descended into the shaft using a safety rope, but the rope broke, and once that problem was resolved he ran into a construction work slag heap. Before he could get anywhere near the cats he had to remove some of the slag, take it to the top, descend again to get more slag and take that to the top, repeating this process many times.

That was all captured on video, and it pains him each time he watches it, he says. Last year, too, a cat cafe in Chengdu on the verge of bankruptcy was found abandoned, with cats locked in cages and feces everywhere. An investigation into this cafe brought to light evidence of similar cases in the country.

The breeding ground for the cat cafe horror was a market that makes it all too easy to set up such businesses, Xu says.

"You may want to get into this field and have your own cash cow, but the bottom line is that to be worthy of this calling you need to regard life as sacred and to really look after the cats. I'm keen to see that there are tighter regulations to keep market forces in check."

Injuries while rescuing cats are common, he says, and that of course includes being scratched or bitten by cats.

In addition to physical scars, Xu and those who work with him also face emotional challenges. Some people take a dim view of what they are doing and even refer to cat and dog lovers in a sneering way, he says. Xu draws on a saying common on the internet according to which "You may be unable to love them, but please do not harm them."

"It is a very complicated issue," he says. "Right now it's the concept of pet raising we are changing, and laws are needed to protect small animals. Promoting adoption rather than purchase is also something we devote ourselves to."

The most conspicuous entrance of the rescue center is a wall in front of which hangs a large red curtain. In this room everyone who adopts a cat goes through a ceremony akin to a Chinese marriage officiation: reading an oath of care, having a photo taken just as newlyweds would, and being issued a certificate.

Here, 300 yuan ($47) is the minimum charge, the paid adoption including three free vaccine shots. Xu insists on the charge, saying he believes that it helps ensure that anyone wanting to truly care for a cat will be made conscious of the minimum they will need to spend on their companion every month.

All that then remains is, as in the aftermath of a marriage ceremony, to live up to the promise to accompany the cat for a lifetime.