This question could also be phrased as 'why should we hire you?'.

☛ Your answer should partly be based around your skills (such as teamwork), and your enthusiasm for the industry, the job and the company.

☛ If you have studied an industry-related degree, consider what you can offer in terms of your technical knowledge: during your course you should have been exposed to the latest thinking in terms of sustainability and methodology. While you should not make out you know it all, your knowledge should add some value to the team.