There’s a factory in Asia that uses only a single litre of water to make a pair of jeans. That’s 346 litres less than Levi-Strauss estimated it took to make a pair of its jeans in 2015. Wouldn’t you love to buy your jeans from this amazingly innovative factory? Me too, but I don’t even know what it’s called.

The manufacturer in question does not want to tell anyone about its groundbreaking water-conserving techniques – not even the companies it supplies. It is one of many practising “secret sustainability”, whereby innovations are silently enacted and kept from the rest of the industry.

This phenomenon is not limited to the clothing industry. The UK organic groceries market has been expanding steadily for the past eight years. The Soil Association estimates that it increased by 5.3% in the past 12 months and is now worth £2.2bn a year. So you would expect any food or drink manufacturer renouncing pesticides and artificial fertilisers in favour of organic production methods to let potential customers know, if not via a PR campaign, then at least on the label or via accreditation.

To flag one area of innovation might attract attention to less sustainable areas, sparking accusations of green-washing

This is not the case for two Portuguese wineries that have quietly switched from conventional to organic practices. They made the switch out of concern for the health of their soils (excessive use of fertiliser can reduce the nutrients in soil, leading to poorer harvests). Instead of buying pesticides and artificial fertilisers, they have invested heavily in labour and technology. They now use drones with sophisticated sensors, and employ software that can predict potential issues affecting soil or vine health. The result is healthier soil, healthier vines and an 18% harvest increase per hectare, with a significantly reduced environmental footprint. And they haven’t told their retail customers.

Why would firms spearheading sustainable practices not publicise their good work? It’s a question that puzzles Professor Steve Evans, director of research in industrial sustainability at Cambridge University’s Institute for Manufacturing, who suggests that such examples are widespread. He believes this stems from a common perception that there must be some kind of downside to the introduction of sustainable practices: either a reduction in product quality, or an increase in the price of manufacturing, or both. In the case of the Portuguese wineries, both already had good reputations for quality. All they wanted to do was to keep giving consumers great wine at a good price, without degrading their soil. They hadn’t increased the cost of making wine as they shifted to organic practice. Their management was concerned that introducing the organic designation would lead consumers to question the quality of their wine. They also feared that if they raised their prices to meet the expectation that organic wine costs more, they risked making their wine unaffordable to their current customers. Why rock the boat? Consumers seem to believe that products cannot become more sustainable without becoming more expensive. So anything to the contrary is met with suspicion.

There are other reasons why manufacturers keep quiet about their sustainable practices. After 15 years of dedicated effort, a well-known car manufacturer reduced the amount of energy it took to make its cars by 75%: it can now make four cars using the same amount of energy it formerly took to make one. Evans was amazed when he discovered this while working with the manufacturer and asked if he could tell the world. It refused, not because the innovations were trade secrets, or because it risked losing a cost-saving competitive edge (due to cheap electricity prices, the cost saving amounted to less than 1%), but because the management was worried that to flag one area of innovation in the business for praise might attract unwanted attention to parts of its operation that were less sustainable, potentially sparking accusations of “green-washing”.

Evans claims that, in business-to-business transactions, there may be even less incentive to advertise sustainable practices. Suppliers fear that talking to their price-sensitive business customers about sustainable changes could be seen, at best, as a meaningless distraction when management should be focused on quality and, at worst, as a signal that costs are about to go up. For companies championing a given innovation, it’s an unnecessary risk: you are unlikely to get any other business customers to sign up based on your sustainability credentials, but you might spook those who fear an increased cost being passed on to them. So best to stay quiet.

All these factors combine to create countless industries where pioneers are creating solutions to reduce environmental harm but are leaving other industry players and consumers in the dark. Evans says: “When we started our research 15 years ago, we believed the problem was that we didn’t have enough examples of sustainable industrial practices for others to follow.”

But he and others at the institute have now found that even with the examples they have been able to share, companies and consumers seem unable to accept that sustainability does not have to cost more to create an equally good product. Apparently, we simply cannot believe that a business can be equally or more profitable while reducing its environmental harm. This is despite an increase in evidence that actively investing in sustainable practices helps business thrive. An example is provided by the Dow Jones Sustainability Indices, a series of benchmarks assessing the sustainability of companies around the world. Research has repeatedly shown that those at the top end of the benchmark outperform those at the bottom.

Libby Peake, senior policy adviser at Green Alliance, an independent thinktank and charity that focuses on environmental leadership in industry and government, agrees. She says: “We know that the best manufacturers are improving their energy efficiency about five times faster than the average company. These leaders have vital lessons to share with the laggards, so it’s a sad state of affairs if they feel they cannot boast about their achievements. We need to see sustainable goods and services move to the mainstream instead of being hidden in the shadows.”

Green Alliance has shown that while people’s attitudes are overwhelmingly supportive of resource efficiency, 45% of people actively distrust big businesses, according to a large survey, with workshop interviews finding that many people believe green goods are always more expensive.

This belief persists despite more sustainable and resource efficient businesses demonstrating clear competitive advantages.

Evans is collaborating with psychologists from Cambridge University on research to change the public’s belief about the expense and quality of sustainable products.

“The hardest thing to change is your mental model – your belief about how the world works,” says Evans. It seems tackling some of the biggest environmental problems in industry is not as hard as getting people to change their minds.