In short: CBSE has rationalized the syllabus over the past few years under NEP 2020. Several chapters and topics have been removed from the board exam or moved to internal assessment. This guide lists exactly what is deleted for 2026-27 so you do not waste study hours on content that will not appear on your paper.
Why This Matters
The NCERT textbook still contains all chapters — deleted ones are not physically removed from the book. Students who study the full textbook without checking the official syllabus end up spending 15-20 hours on chapters that carry zero marks on the board exam.
Those 15-20 hours could be spent on practice papers, revision, or strengthening weak chapters that ARE on the exam.
Class 10: Deleted Topics and Chapters
Science
| Deleted/Reduced | Details |
|---|---|
| Periodic Classification of Elements | Removed from the board exam in the rationalized syllabus. This was Chapter 5 in NCERT. |
| Sources of Energy | Chapter 14 removed from the theory exam. |
| Management of Natural Resources | Chapter 16 moved to internal assessment/project work. Not on the theory paper. |
| Control and Coordination | Parts of this chapter have been reduced. Check the official syllabus for which sections remain. |
What remains: 10-11 chapters covering Chemical Reactions, Acids/Bases, Metals, Carbon Compounds, Life Processes, Reproduction, Heredity, Light, Electricity, Magnetic Effects, and Our Environment. These carry the full 80 marks.
Focus your energy on these using the Science marks weightage guide.
Mathematics
| Deleted/Reduced | Details |
|---|---|
| Constructions | The full chapter on constructions (dividing line segments, constructing tangents) has been moved to internal assessment. It will NOT appear on the theory paper. |
| Parts of Real Numbers | Some exercises have been trimmed. The Fundamental Theorem of Arithmetic and irrationality proofs remain. |
What remains: 14 chapters covering all of Algebra, Geometry, Trigonometry, Coordinate Geometry, Mensuration, Statistics, and Probability. See the Maths weightage guide.
Social Science
| Deleted/Reduced | Details |
|---|---|
| Forest and Wildlife Resources | Geography Chapter 2 — check if it is in internal assessment for your year. |
| Some sections of Democracy and Diversity | Political Science Chapter 3 has been partially reduced in previous years. |
What remains: The core chapters for History (Nationalism in India, Making of a Global World, Age of Industrialisation, Print Culture), Geography (Resources, Agriculture, Minerals, Manufacturing, Lifelines), Political Science (Power Sharing, Federalism, Political Parties, Outcomes of Democracy), and Economics (Development, Sectors, Money and Credit, Globalisation, Consumer Rights).
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Class 12: Deleted Topics and Chapters
Physics
| Deleted/Reduced | Details |
|---|---|
| Communication Systems | The full chapter has been removed from the board exam. |
| Some parts of EM Waves | Reduced to basic properties and spectrum. Detailed derivations removed. |
What remains: 14 chapters from Electrostatics through Semiconductor Electronics. See the Physics weightage guide.
Chemistry
| Deleted/Reduced | Details |
|---|---|
| Polymers | Reduced weightage — only basic classification and examples remain. Detailed polymerization mechanisms deleted. |
| Chemistry in Everyday Life | Reduced to basic drug classification and cleansing agents. Detailed pharmaceutical chemistry deleted. |
| Surface Chemistry | Some advanced topics on catalysis have been trimmed. |
What remains: The core of Organic Chemistry, Physical Chemistry, and Inorganic Chemistry. See the Chemistry weightage guide.
Biology
| Deleted/Reduced | Details |
|---|---|
| Strategies for Enhancement in Food Production | Reduced scope — tissue culture and SCP still included, some detailed breeding methods removed. |
| Parts of Environmental Issues | Some specific pollution case studies removed. Core concepts remain. |
What remains: The core of Reproduction, Genetics, Biotechnology, Ecology, and Human Welfare. See the Biology weightage guide.
Mathematics
| Deleted/Reduced | Details |
|---|---|
| Mathematical Reasoning | Removed from the board exam (was in Chapter 14). |
| Some exercises in Relations and Functions | Binary operations section has been trimmed. |
What remains: Calculus (the largest section at 35 marks), Algebra, Vectors + 3D Geometry, Probability, and Linear Programming. See the Maths weightage guide.
Important Caveats
- Check the official circular. The deleted topics list can change slightly each year. Always verify at cbseacademic.nic.in.
- Deleted topics may appear in internal assessment. Just because a topic is not on the theory paper does not mean you can completely ignore it. Your school may include it in projects or practicals.
- MCQs sometimes test boundary topics. In rare cases, an MCQ might touch on content that is technically in a reduced chapter. Read the chapter headings even for deleted chapters so you are not completely blind.
How to Use This Information
- Cross out deleted chapters in your NCERT textbook. Put an X on the first page of each deleted chapter. This prevents accidental studying.
- Reallocate that time to high-weightage chapters. The hours you save from not studying Periodic Classification, Sources of Energy, and Communication Systems can go into more practice on Life Processes, Electricity, and Electrostatics.
- Focus on the sample paper. The 2027 sample paper (released Sep 21) only includes questions from the included syllabus. If a topic appears in the sample paper, it is definitely in the exam. If it does not appear, cross-reference with the syllabus.
Frequently Asked Questions
Will deleted topics be asked in the board exam?
No. Topics listed as deleted in the official CBSE syllabus circular will not appear on the theory paper. CBSE examiners set papers strictly according to the published syllabus.
Can I get marks from deleted topics in internal assessment?
Yes. Your school may include deleted topics in projects, practicals, or internal tests. Check with your teachers about what is included in the 20-mark internal assessment.
Does the NCERT textbook remove deleted chapters?
No. The NCERT textbook is printed with all chapters intact. CBSE deletes topics through a separate circular, not by changing the textbook. You need to manually identify which chapters to skip.
Is the deleted syllabus the same for 2027 as it was for 2026?
Mostly yes. CBSE has confirmed that the assessment pattern and syllabus rationalization remain unchanged for 2026-27. However, always check the latest circular for any minor updates.
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