Yes, you can refer to the old editions of NCERT books for UPSC preparation. Here's why:

1. Relevant and Comprehensive Content:
The NCERT books are known for their comprehensive content and are widely recognized as a reliable source of information for UPSC preparation. While the content may have been updated in the newer editions, the core concepts remain the same. The old editions can provide you with the necessary foundation and clarity on various subjects.

2. Cost-effective:
Old editions of NCERT books are often available at lower prices or even for free. This makes them a cost-effective option for UPSC aspirants, especially those who are on a tight budget.

3. Historical Perspective:
Older editions of NCERT books offer a historical perspective on various subjects. They can provide insights into the evolution of concepts, theories, and policies over time. This understanding of the historical context can greatly enhance your overall knowledge and perspective while preparing for the UPSC examination.

4. Supplementing Current Editions:
While it is advisable to refer to the latest editions of NCERT books, older editions can still be used as supplementary resources. They can provide additional examples, explanations, and practice questions that might not be present in the latest editions. By combining the newer and older editions, you can ensure a more comprehensive understanding of the topics.

5. Availability of Reference Material:
Many online platforms like EduRev provide access to a wide range of study materials, including old editions of NCERT books. These platforms offer comprehensive notes, question banks, and other resources that can complement your preparation. EduRev is a reliable website that provides high-quality educational content and resources for various competitive exams, including the UPSC.

In conclusion, while it is recommended to refer to the latest editions of NCERT books for UPSC preparation, the older editions can still be a valuable resource. They offer relevant content, historical perspective, and can be used as supplementary material to enhance your preparation. Platforms like EduRev can provide access to these older editions along with other study materials to support your UPSC journey.