We conducted a materiality assessment based on the GRI Standards to identify the topics that pose greater impacts on us and our stakeholders, and from there we determined the report contents accordingly. The materiality assessment process consists of the following three major steps:

To help distinguish topics about sustainability development in which stakeholders concern, we have been holding stakeholder engagement exercises through an independent consultant every year since 2012-13, where we invited different stakeholder groups such as staff, contractors, consultants, green groups, academics, members of the public and councilors to collect their issues of concern as well as their feedback and suggestions on our work about sustainability development².

To prepare this Report, we conducted focus group meetings and questionnaire surveys between April and June 2018 through independent consultants, inviting environmental and academic groups to discuss issues about the environment and other sustainable development matters relating to DSD. We have selected 18 material topics based on the results of the materiality assessment and recommendations made by stakeholders, senior management and our Taskforce on Sustainability Reporting. This Report includes six additional topics of concern which were not addressed in previous reports, mainly focusing on the performance of our contractors and staff. Topics include suppliers'/contractors' performance on environmental management, corruption prevention, occupational health and safety, staff training and support, grievance mechanism, as well as local employee ratio and employment policy³. While making our best effort to present accurate data and information, we do not have direct control over some data and information which are provided by relevant parties that are beyond our direct remit.

Material topics covered in this Report and their corresponding boundaries are tabulated below: