What it is
The National Standard Examination in Biology (NSEB) is the first stage of India’s route to the International Biology Olympiad (IBO). The Indian Association of Physics Teachers (IAPT) conducts it, working with the Association of Teachers in Biological Sciences (ATBS). From the second stage onwards, the Homi Bhabha Centre for Science Education (HBCSE) in Mumbai runs the programme, which is funded by the Government of India.
Biology olympiads surprise many students. They are less about remembering facts and more about reading an experiment, interpreting data and reasoning from what you know to something you have not seen before. HBCSE notes that olympiad questions, while within the syllabus, are usually unconventional and of a high difficulty level.
Who can take it
NSEB has the same eligibility as the other senior science exams. For the 2026–27 cycle, that meant:
- being in Class 10, 11 or 12, and born within a set birth-date window;
- being eligible to hold an Indian passport (students with OCI cards can go up to the selection camp, but under current court orders cannot be chosen for the Indian team);
- having lived and studied in India, or studied in an Indian school system, since a cut-off date;
- not having finished Class 12 board exams, or started university, before the set dates;
- not writing NSEJS in the same year.
These rules change and are applied strictly. Check the official eligibility rules for this year on IAPT’s and HBCSE’s sites before enrolling.
The paper
In the 2026–27 cycle, NSEB was a two-hour multiple-choice paper at Class 12 level: 48 single-answer questions with a penalty for wrong answers, and 12 questions with one or more correct options, credited only when exactly the right ones are marked. It was offered in English, Hindi and several other Indian languages. HBCSE’s syllabus covers diversity of life, cell biology, plant and human physiology, reproduction, genetics and evolution, biology and human welfare, and ecology, and it expects general science up to Class 10 and mathematics up to Class 12.
The stages
| Stage | Who | What happens |
|---|---|---|
| NSEB | Eligible students in Classes 10–12 | Two-hour multiple-choice paper |
| INBO | Selected from NSEB | The Indian National Biology Olympiad, a written exam at centres across India |
| OCSC | Top INBO scorers | About two weeks at HBCSE, with theory and practical tests |
| Pre-departure training | The selected team | Theory and laboratory training at HBCSE |
| IBO | India’s team of four | Theory and practical exams, usually in July |
Students who qualify for INBO must register on HBCSE’s site to get their admit card; without that registration they cannot sit the exam.
How selection treats younger students and girls
Two features of the selection rules are worth knowing, especially for families of Class 10 and 11 students and for girls.
First, Class 12 students and students in Classes 10 and 11 are ranked in separate groups, with separate cut-offs, for both the national olympiad and the camp. For 2026–27, HBCSE set a target of 20 camp places for each group in biology. A younger student is therefore not competing head to head with Class 12 students until the final team selection at the camp, which uses one combined merit list.
Second, there is a supernumerary quota for girls: if fewer than a fifth of the students selected for the national olympiad in a subject are girls, more girls are added in order of merit, as long as they meet the minimum score. Our NSEP page explains the rest of the selection rules.
When it happens
Schools usually register as exam centres in August, and students enrol through their school or directly on IAPT’s site, usually from late August into September. NSEB is usually written in November. In the 2026 timetable the four senior exams had separate slots, so one student could write more than one; check the current timetable before planning on it. INBO usually falls around late January or early February, the biology camp in the spring, and IBO in July. Always check this year’s dates on the official sites.
How to prepare
Strong NSEB preparation looks different from board revision:
- Read NCERT biology for Classes 11 and 12 closely, including diagrams, tables and boxed examples. Many questions start there and go further.
- Practise with data. Read graphs, tables and experimental set-ups and ask what they show and what they do not.
- Use your physics and chemistry. Physiology, biochemistry and ecology questions often need them.
- Solve past papers. IAPT publishes past NSE papers with answer keys, and HBCSE publishes past INBO papers with solutions.
- Build practical skills. The camp and IBO test laboratory work; HBCSE publishes a handbook of experimental tasks in biology.
It is normal to find the paper hard at first, and an early attempt in Class 10 or 11 is good experience. See our science prep guide for a weekly routine.
Where daily practice fits
A daily quiz cannot teach experimental reasoning, but it can keep a wide base of science fresh. Ado is a free daily quiz of 8 questions, including a 60-second sprint, in maths, science, English, GK and reasoning, ranked only against students the same age, and its Ado Rank builds from a student’s top three subjects and never resets. Use it for habit and breadth, and keep the real biology olympiad work for longer sessions with past papers and data.