The to-infinitive has many different usages, but what underlies all of them is the sense that something has the potential (likelihood) to happen. Starting with simple cases, 1. I have a task to do == I have a task that I should do. 2. There is a task to do == There is a task that (someone) should do. In (2), it say the task should be done without specifying "who" should do it. The infinitive has a standard way of specifying who does it - we add "for [someone]" before "to". For example, - There is a task FOR ME to do == There is a task that I should do. - It is time FOR YOU to go == It is time that you should go. Your example has the same structure. - the need FOR [a full environmental impact assessment] TO be carried out first == the need that [a full environmental impact assessment] should be carried out first. "a full environmental impact assessment" is abstract but has the same role of the agent that does the action. "a full environmental impact assessment should be carried out" is another way of saying "the environmental impact should be fully assessed".

Hi there! In sentences like this, you can put "is going" before "to", and put a "that" to make things clearer : "citing THAT the need for an assessment IS GOING TO be carried out first" - See how it makes sense now? :) Greetings

"To carry out" means to finish an assigned task, often in the context of business or politics "To be carried out" is the passive voice form of "to carry out". For example: Active voice - "Steve will carry out the new policy." Passive voice - "The new policy will be carried out by Steve."