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National Institute of Open Schooling · Free

NIOS Books — accessible, exam-ready supplements.

NIOS material is written for self-study at the secondary and senior-secondary level, which makes it unusually well-suited to UPSC's structured-knowledge expectations. We list subjects covered, with direct links to the official PDFs.

9
Subjects
Free
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NIOS.ac.in
Source
UPSC-tagged
With syllabus mapping