For future climate conferences fossil fuel delegates will need to share their industry ties.
This marks a large shift in the ease for oil and gas employees to attend, with more than 600 present at COP27.
The move will see less influence given to people who work in the industry over proceedings at the events and it has been welcomed by campaigners.
Rachel Rose Jackson from Corporate Accountability, which works to prevent companies from harming the planet, said: “It’s actually no small thing that for the first time ever, all participants, will have to be honest to the world about who they are.”
Previously, allegations have been made that certain attendees are not truthful about their links to fossil fuels and have not needed to be to gain entry.
However, for COP28 this November the rules will come into play.
The UN’s Simon Stiell said: “From now onwards, every single badged participant attending the event will be required to list their affiliation and relationship to that organisation.”
COP27 saw bp’s boss Bernard Looney sign up as a Mauritanian delegate, a nation where the company has business – but this change would prevent this moving forward.
Global Witness worked to provide data on the number of attendees linked to the fossil fuel industry at the last two COP events.
Alice Harrison from the NGO said: “This information should help prevent those representing the interests of fossil fuels from sneaking through the back door without declaring their true intentions. We’ll be certain to dig into those who refuse to declare.”