A dog is packed in a box. Photo: screenshot of video posted by The Beijing News on Sina Weibo

Two express companies in Chengdu, Southwest China's Sichuan Province involved in selling and delivering blind boxes containing live animals have been fined 30,000 yuan ($467) and 50,000 yuan respectively, local authorities announced on Saturday.

"We will strengthen supervision of services that sell and deliver live animals," an official with the Sichuan Provincial Postal Administration said, according to a report from the China News Service.

More than 160 living pets were found to be packed in "blind boxes" at an express station in Chengdu, Southwest China's Sichuan Province on Monday, waiting to be sold, and until Tuesday, these pets except for four that had already died were rescued by local residents and volunteers, and temporarily housed in pet shops and hospitals.

The cats and dogs in the boxes were between one month and three months old and most of them were on the verge of suffocating before being saved by volunteers from a package sorting facility, as reported by the Beijing News.

The company operating the facility, ZTO Express that has been listed in the US, responded on Tuesday on Sina Weibo, saying that these blind boxes of living pets were sold on e-commerce platforms and the express station agreed to send them which represented a violation of regulations.

"The facilities operations have been suspended and all staff will cooperate with the authority to investigate the case," the announcement said.

Blind boxes are found in Chengdu, Southwest China's Sichuan Province. Photo: screenshot of video posted by The Beijing News on Sina Weibo

The company's announcement did not quiet down the anger of netizens who condemned repeated emergence of blind boxes of living pets as a business. "All related people in the case, sellers, buyers and express companies, should be punished. The business treats life as dust," one netizen commented.

An official of the Chengdu Agricultural and Rural Bureau surnamed Li said on Tuesday that the case has been reported to them and is in investigation. 

The business of blind boxes that hide products in the boxes to trigger surprise and delight now covers many fields and packing living pets in blind boxes have been criticized by Chinese netizens although has yet to be formally banned.

The advertisements of these blind boxes on e-commerce platforms often said that the pets are "purebred," but when customers received the boxes, many of them found the pets were a ranged from strays to mixed breeds typically seen in rural parts of the country.

Many animals die in transit, expiring before they arrive to the purchaser, or during the return journey.