The ethical responsibilities of an IAS officer, highlighted in the UPSC syllabus, include maintaining integrity, impartiality, and accountability in public service. IAS officers are expected to uphold the Constitution and work towards the welfare of all citizens, ensuring that their actions reflect public interest. They must adhere to the principles of good governance, transparency, and responsiveness while addressing issues like social justice and environmental sustainability. Ethical conduct is crucial as it forms the foundation of trust between the government and the public, influencing the effectiveness of administration.