At overseas international travel exhibitions, there are European sustainable tourism advocacy organizations, and they went to the booths of Taiwanese operators to ask them about their understanding of sustainable tourism. At that time, Zhang Shiyi thought: flaunting sustainability seems to be beneficial to the company's image building. But she really appreciates the importance of sustainability to the tourism industry.

In 2018, Royal Caribbean Cruises, an international client of NagaWorld, became a member of the Global Sustainable Tourism Council (GSTC), promising to formulate a clear sustainability Development goals, including the end of 2020, to launch 1,000 sustainable tourism certified by GSTC partner photo retouching certification bodies around the world. This means that the landed shore tourism travel agencies in various countries that cooperate with this cruise industry leader are expected to accelerate their pace and obtain international certification. GSTC is an independent organization recognized and supported by the United Nations.

Its members include tourism and hotel operators, NGOs, national and local government agencies, local communities, etc. It is engaged in the formulation and promotion of global sustainable tourism standards. It does not directly certify sustainable tourism, but through professional certification agencies. The Tourism Bureau of the Ministry of Transportation of Taiwan is also a member of GSTC. The 2020 "Taiwan Tourism Policy White Paper" mentioned that the tourism industry is encouraged to refer to the GSTC's global sustainable tourism guidelines to independently promote plans and obtain c