Dark mode is more energy efficient.
Claims must not be likely to mislead, and the basis for them must be clear.
The overall presentation of the communication, including words, symbols, and imagery, as well as missing information, can all contribute to the audience being misled.
Even if those claims are factually correct, they should not mislead the consumer by giving an inaccurate impression. They must only give the impressions that a product, service, process, brand, or business is as environmentally friendly or sustainable as it really is.
For example, a business should not claim that a product is “recyclable” if only parts of it can be recycled and other parts cannot. Likewise, claiming that a product is “organic” when only parts of it are considered organic is almost certainly misleading. The generally understood meaning of ‘organic’ is that virtually the entirety of the product meets that description. When a brand wishes to claim that their products are partly made from organic cotton, they should clearly state to what extent it is made from the organic material (e.g. these sweaters are manufactured from 47% organic cotton).