Welcome to the official website of 2025 the 9th International Conference on Energy and Environmental Science (ICEES 2025) to be held in Chongqing, China during March 21-23 . ICEES2025 will be sponsored by Chongqing Jiaotong University, China and Chongqing University, China. ICEES is an annual conference which aims to present the latest research and results of scientists (professors, doctoral students, and post-doc scientists) related to Energy and Environmental Science topics. This conference provides opportunities for delegates from different areas to exchange new ideas, applications and experiences face to face, to establish business or research relations, and to find global partners for future collaboration. We hope that the conference results in significant contributions to the knowledge base in these scientific fields. ICEES features invited keynote speeches, peer-reviewed paper presentations, and academic visit. The conference is completely open (one needs to register first), you will not have to be an author or a discussant to attend. With the successful experience of the last five years in Thammasat University, Thailand, University of Malaya, Malaysia, Seoul, South Korea, and Perth, Australia, as well as virtually in 2021-2023 and Chongqing in 2024, we will see that ICEES 2025 will come back to China to achieve another success and provide a better platform for all the participants to have fruitful discussions and to share ideas of researches.