A whiff meter on a shopping mall’s new high-tech public loos is warning shoppers in China which booths are like a breath of fresh air and which are too stinky to use.

The loos -at a shopping centre in Chengdu, in Sichuan Province – come with their own smelly-vision screen at the entrance.

Potential users can check to see which stalls are ready for action and which need to be left for five minutes.

The screens show images of individual cubicles in the men’s and women’s sections with their own stink rating allowing shoppers to take their pick.

High-tech sensors measure the levels of toxic odours that are still lingering in the air from the last user.

The invention is a godsend for caught short shoppers who do not want to blunder into the after-effects of someone else’s curry or spicy bean stew.

Footage of the new loos shows a woman ridiculing the technological marvel as she studies the ‘odour index’ to choose which loo is the safest to use.

The woman – not named in local media – had filmed herself making fun of the bizarre discovery.

In the video, she points towards a large screen on display outside the public loo door in the mall showing how much each of the stalls smells.

The woman can be heard trying to hold back her laughter and saying (in Chinese): “Such ‘high technology’ is not necessary!”

She later shared the video on Douyin – the Chinese version of TikTok – leaving netizens just as baffled as she appears to be.

One user, under the handle ‘Big waves washing sand 181’ jokingly commented: “Maybe it can also detect whether there are gynaecological diseases.”

Another user, ‘spend together’ had a better idea of what technological advances should be used for and said: “Install a monitor in every toilet to check whether there are cockroaches and mice in the toilet.”

And user ‘Fat Boy Snail Noodles (Xiaoxi Street)’ was seemingly worried about the situation and asked: “Will this spy on you?”