The UPSC Combined Geo-Scientist Examination is conducted for scientific and technical posts in the Geological Survey of India and Central Ground Water Board. It is designed for candidates with relevant qualifications in geology, geophysics, chemistry and hydrogeology.

CGSE 2026 at a glance

The official Preliminary notification was dated 3 September 2025. The Combined Geo-Scientist Preliminary Examination was scheduled for 8 February 2026, and the Main Examination for 20 and 21 June 2026. Applications were accepted up to 23 September 2025 at 6:00 PM through the new UPSC online application portal.

The notification reported approximately 78 vacancies, subject to alteration. The posts included Geologist, Geophysicist and Chemist in the Geological Survey of India, and Scientist B and Assistant-level posts in Hydrogeology, Chemistry and Geophysics in the Central Ground Water Board.

Posts and organisations

Category I covers posts in the Geological Survey of India under the Ministry of Mines: Geologist Group A, Geophysicist Group A and Chemist Group A.

Category II covers posts in the Central Ground Water Board under the Ministry of Jal Shakti: Scientist B in Hydrogeology, Chemical and Geophysics, Assistant Hydrogeologist, Assistant Chemist and Assistant Geophysicist.

Candidates may apply for one or both categories if they satisfy the relevant qualification conditions. Read the current rules carefully because a qualification suitable for one post may not be sufficient for another.

Vacancies in the 2026 notice

The notice listed 39 Geologist, 2 Geophysicist and 15 Chemist vacancies in GSI. It listed 5 Scientist B Hydrogeology, 2 Scientist B Chemical, 1 Scientist B Geophysics, 18 Assistant Hydrogeologist, 2 Assistant Chemist and 1 Assistant Geophysicist vacancy in CGWB. Nine vacancies were reserved for PwBD candidates in the Geologist post. These numbers are approximate and liable to alteration.

Selection stages

CGSE has three successive stages: Preliminary Examination with two objective papers, Main Examination with three descriptive papers, and Personality Test or Interview. Preliminary marks are counted for final merit. Candidates who qualify the Preliminary stage are admitted to the Main examination, and candidates qualifying the Main stage are called for the Personality Test.

Eligibility overview

Eligibility depends on the post and discipline. Candidates need the relevant master's degree or equivalent qualification specified in the rules, such as geology or applied geology for Geologist, relevant geophysics or physics qualifications for Geophysicist, chemistry or applied chemistry for Chemist, and hydrogeology-related qualifications for hydrogeology posts. Always verify the exact degree, subject combinations, age limit, nationality, medical and physical standards in the latest notification.

Application process

Create an account on the UPSC online portal, generate the Universal Registration Number, complete the Common Application Form and then complete the examination-specific form. The 2026 notice stated that the previous OTR module would not apply and candidates had to fill the new portal modules afresh.

Keep a photo ID, recent photograph, signature, degree and marks documents, category certificate and other supporting documents ready. The notice required details and a scanned copy of the photo ID used for Universal Registration. Review the form carefully because changes and withdrawal may not be allowed after submission.

Preparation strategy

Begin with the official syllabus for the post or category selected. Revise core concepts, practise objective questions for Prelims, and start descriptive answer writing early for Mains. Build diagrams, maps, flowcharts, formula sheets, mineral and rock identification notes, field-method notes and an error log.

For the common paper, prepare current issues related to earth sciences, water resources, environment, natural hazards, exploration, energy and public policy. Solve official previous papers under time limits and classify mistakes by concept, calculation, recall and time management.

Official links

• CGSE Preliminary 2026 notification
• UPSC active examinations
• UPSC previous question papers
• UPSC online application portal

This evergreen guide should be used with the latest UPSC notice for dates, vacancies, qualifications and service rules.

The Combined Geo-Scientist syllabus is discipline-specific. Candidates should first identify the post or category for which their qualification is valid, then prepare the relevant geology, geophysics, chemistry or hydrogeology syllabus for both objective and descriptive papers.

Examination syllabus structure

The Preliminary stage has two objective papers and screens candidates for the Main stage. The Main stage has three descriptive papers. The Personality Test follows the written stages. The official rules and notification appendices are the final authority for the exact paper names, marks, duration and syllabus wording.

Geology syllabus areas

Geology preparation commonly includes physical geology, geomorphology, structural geology, mineralogy, petrology, stratigraphy, palaeontology, economic geology, Indian geology, engineering geology, hydrogeology, remote sensing, geochemistry, environmental geology and field methods.

Prepare rock and mineral identification, geological maps, folds and faults, plate tectonics, Indian stratigraphic provinces, ore deposits, groundwater systems, geological hazards and exploration methods. Practise labelled diagrams and short descriptive answers.

Geophysics syllabus areas

Geophysics preparation commonly includes mathematical methods, theoretical seismology, geophysical potential fields, gravity and magnetic methods, electrical and electromagnetic methods, seismic methods, well logging, geophysical signal processing, earth physics and exploration geophysics.

Maintain formula sheets for units, transforms, wave behaviour, potential fields, resistivity and seismic concepts. Practise interpretation questions and learn to explain the assumptions behind each exploration method.

Chemistry syllabus areas

Chemistry preparation commonly includes atomic structure, chemical bonding, thermodynamics, chemical equilibrium, electrochemistry, kinetics, inorganic chemistry, coordination chemistry, analytical chemistry, organic chemistry, spectroscopy and instrumental methods.

Revise reactions, mechanisms, qualitative analysis, numerical chemistry, instrumental principles and common analytical errors. Practise both calculation-based and conceptual questions under time limits.

Hydrogeology syllabus areas

Hydrogeology preparation commonly includes groundwater occurrence and movement, aquifers, wells, Darcy law, groundwater flow, well hydraulics, hydrochemistry, water quality, groundwater exploration, recharge, artificial recharge, contamination, watershed concepts and groundwater management.

Use diagrams for aquifer types, flow nets, wells and recharge structures. Connect hydrogeology with Indian water resources, drought, contamination, irrigation and sustainable management.

Common preparation areas

Read current developments connected with earth science, groundwater, mineral resources, energy, climate, natural hazards, environmental protection, mapping and public infrastructure. Use official previous papers to identify recurring concepts. Do not prepare only for Prelims; descriptive Mains answers need early practice.

How to build a syllabus tracker

Create a tracker with columns for official topic, first reading, short notes, objective practice, descriptive answer, previous-paper questions and revision. Keep a separate error log for factual recall, diagrams, calculations and interpretation. Revisit weak topics at planned intervals instead of waiting for the final month.

Study plan

First complete fundamentals and official syllabus mapping. Next solve topic-wise objective questions and prepare concise notes. Then add weekly descriptive answers, mixed papers and full-length tests. In the final phase revise diagrams, formulae, maps, mineral and rock facts, hydrogeology concepts, current applications and repeated previous-paper themes.

Official sources

• CGSE Preliminary 2026 notification
• UPSC previous question papers
• UPSC revised syllabus and scheme

The exact syllabus depends on the category and post. Confirm the latest official PDF before finalising preparation.