Reliable sources for current affairs in UPSC preparation include reputed newspapers like The Hindu and Indian Express, which provide comprehensive coverage of national and international issues. Additionally, monthly magazines such as Yojana and Kurukshetra delve into critical topics relevant for the exam. Online platforms like PIB (Press Information Bureau) and various government websites are also vital for updates on policies and schemes. Engaging with credible online courses and coaching materials can further enrich understanding. By combining these sources, aspirants can maintain a well-rounded perspective on current affairs crucial for the UPSC.