UPSC CGS Mains
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LATEST UPDATE
The Union Public Service Commission Combined Geo-Scientist (CGS) Preliminary Examination for the 2026 cycle is scheduled to be held on 8 February 2026, with the exam conducted in two shifts. The official notification for UPSC CGS 2026 was released on September 3, 2025, and the application window closed on September 23, 2025. Candidates who successfully clear the Preliminary Examination will be eligible to appear for the Main Examination, which is scheduled to take place on 20 June 2026.
IMPORTANT DATES
The important dates for the UPSC Combined Geo-Scientist (CGS) Examination 2026 (as per the official notification No. 01/2026-GEOL dated 03.09.2025 and consistent updates from UPSC sources) are as follows. These are fixed unless changed by UPSC (check upsc.gov.in for any updates).
Events | Date |
UPSC CGS Notification 2024 | 03/09/2025 |
Online Registration Starts | 04/09/2025 |
Last Date to Apply Online | 23/09/2025 |
UPSC CGS Prelims Exam Date | 08/02/2026 |
UPSC CGS Mains Exam Date | 20/06/2026 |
VACANCY DETAILED
The UPSC Combined Geo-Scientist (CGS) 2026 exam has 85 vacancies in various scientific posts, including Geologist (39), Geophysicist (2), Chemist (15), and several Scientist ‘B’ and assistant-level posts across geological and hydrogeological departments. These positions are Group A and Group B roles recruited through Prelims, Mains, and Interview stages. The exam is conducted at the national level by UPSC with job locations across India.
The categories of post to which recruitment is to be made on the results of this examination and the approximate number of vacancies in the various posts are given below:-
Name of Posts | Number of vacancies |
Geologist, Group A | 39 |
GeoPhysicist, Group A | 02 |
Chemist, Group A | 15 |
NOTE : Following 9 vacancies are reserved for Persons with Benchmark Disability: 09 vacancies of Geologist { 05 Locomotor disability or Cerebral Palsy {OH(OA/OL) and 04 HH} | |
Category II: (Posts in the Central Ground Water Board, Ministry of Jal Shakti, Department of Water Resources, River Development & Ganga Rejuvenation.) | |
Scientist ‘B’ (Hydrogeology) Group A | 05 |
Scientist ‘B (Chemical) Group A | 02 |
Scientist ‘B (GeoPhysics) Group A | 01 |
Assistant Hydrogeologist, Group ‘B’ | 18 |
Assistant Chemist, Group ‘B’ | 02 |
Assistant Geophysicist, Group ‘B’ | 01 |
SALARY STRUCTURE
For the UPSC CGS 2026 recruitment (as per the notification for posts in Geological Survey of India and Central Ground Water Board), selected candidates receive salaries under the 7th Central Pay Commission (CPC) Pay Matrix.
Group ‘A’ Posts (e.g., Geologist Group ‘A’, Geophysicist Group ‘A’, Chemist Group ‘A’, Scientist ‘B’ (Hydrogeology/Chemical/Geophysics) Group ‘A’): These are at Pay Level 10 with starting basic pay of 56,100 (Grade Pay equivalent ?5,400 in pre-7th CPC terms). Gross in-hand salary (including current Dearness Allowance ~58-60% as of early 2026, HRA up to 27% in X-class cities like major metros, Transport Allowance, and other perks) typically ranges from 80,000 – 1,20,000 per month initially, depending on posting city and allowances.
Group ‘B’ Posts (e.g., Assistant Hydrogeologist, Assistant Chemist, Assistant Geophysicist Group ‘B’): These are generally at Pay Level 8 (basic pay starting around ?47,600). In-hand salary is lower, approximately 60,000 – 90,000 per month after adding allowances.
Salaries include benefits like medical facilities (CGHS), pension under NPS, field allowances (relevant for geo-scientific roles involving surveys/exploration), leave travel concession, and job security. Pay increases with annual increments, promotions (e.g., to Senior Geologist after 4-5 years), and future revisions (8th CPC discussions ongoing, potentially from 2026). Exact in-hand varies by location (HRA: 27%/18%/9% for X/Y/Z cities), DA revisions (bi-annual), and deductions (PF, tax, etc.). For precise details, refer to the official UPSC notification or DoPT guidelines post-selection.
HOW TO APPLY
The application window for the UPSC Combined Geo-Scientist (CGS) Examination 2026 (Prelims) closed on 23rd September 2025 (till 18:00 hours), as per the official notification (No. 01/2026-GEOL, dated 03.09.2025). Since the current date is January 12, 2026, applications are no longer open for this cycle — the process has moved past submission to later stages (e.g., admit cards for Prelims on 8th February 2026 are typically issued in the preceding week).
UPSC has introduced a new Online Application Portal with four parts/modules. The old One Time Registration (OTR) is discontinued — you must start fresh on this portal.
- Visit the Official Portal.Go tohttps://upsconline.nic.in
Create an Account (Account Creation)
On the homepage, click to create a new account.
Provide basic details: name, email, mobile number, etc.
Use a valid, active email ID (UPSC communicates via email/SMS).
Strongly recommended: Use Aadhaar Card for seamless ID verification and authentication.
- Complete Universal Registration (Generate URN)
Fill the Universal Registration Number (URN) module.
Provide personal details: date of birth, gender, category (SC/ST/OBC/EWS/General), photo ID card details (Aadhaar/Voter/PAN/Passport/Driving Licence/State-issued ID), etc.
Upload a scanned copy of the chosen Photo ID (mandatory).
This URN is a lifetime — register once and reuse for all future UPSC exams.
You can complete this anytime (even before notification), but it’s required before proceeding.
- Fill the Common Application Form (CAF)
Log in with your URN/account.
Fill personal, educational, category/reservation claims (e.g., SC/ST/OBC/EWS/PwBD/Ex-Servicemen), address, etc.
Upload required documents/scans (photo, signature, certificates if claiming reservation — ensure formats/sizes match instructions).
Photo guidelines: Not older than 10 days from application start date; name and date clearly mentioned; face occupies 3/4th space; appearance must match throughout exam stages (e.g., beard/spectacles consistent).
Pay the application fee (if applicable — usually ?200 for General/OBC males; exemptions for females/SC/ST/PwBD). Payment via online modes (net banking, card, UPI).
- Fill the Exam-Specific Form (4th Part)
Available only during the notification window (e.g., 03.09.2025 to 23.09.2025 for 2026).
Select the exam (Combined Geo-Scientist 2026).
Choose category/posts (Category I for GSI, Category II for CGWB — you can apply for both in one form if eligible, no extra fee).
Select preferred exam centre (first-apply-first-allot basis; limited slots in some centres).
Review all details carefully — no changes/additions/deletions allowed after final submission (even during window, editing is limited to CAF before submission).
- Final Submission and Confirmation
Preview the form.
Submit and pay fee (if not exempted).
Download/print the application confirmation page (with registration number).
No withdrawal allowed after submission.
Important Reminders
Documents to Prepare in Advance: Scanned Photo ID, recent passport-size photo (with date/name), signature, category certificates (EWS/OBC based on recent FY income), etc.
Helpline: For issues (fee payment, uploads), contact 011-23385271 / 011-23381125 / 011-23098543 (or helpline in notification: 011-24041001 during window).
Admit Card: Download from upsconline.nic.in later (e-Admission Certificate, no postal dispatch).
No Offline Mode: Online only — no postal/hand applications accepted.
Provisional Admission: At all stages (Prelims/Mains/Interview), admission is provisional; final clearance after document/medical verification.
EXAM CENTERS
The Exam centres for the UPSC Combined Geo-Scientist (CGS) Examination 2026 are specified in the official notification. The centres differ by stage of the examination.
Prelims Examination
- Ahmedabad
- Bengaluru (Bangalore)
- Bhopal
- Chandigarh
- Chennai
- Cuttack
- Delhi
- Dispur (Guwahati)
- Hyderabad
- Jaipur
- Jammu
Kolkata
- Lucknow
- Mumbai
- Patna
- Prayagraj (Allahabad)
- Shillong
- Shimla
- Thiruvananthapuram
- Noida (Gautam Buddh Nagar)
- Gurugram
- Ghaziabad
- Faridabad
Main Examination
- Bhopal
- Chennai
- Delhi
- Dispur (Guwahati)
- Hyderabad
- Kolkata
- Lucknow
- Mumbai
- Shimla
ADMIT CARD
The admit card or hall ticket for the UPSC Combined Geo-Scientist (CGS) Preliminary Examination 2026 has not yet been released. According to the official notification:
Eligible candidates will be issued an admit card on the last working day of the preceding week of the examination date.
The Prelims exam is scheduled for 8th February 2026 (Sunday).
This means the admit card is expected to be made available for download around late January 2026 to early February 2026 (likely 30th January to 6th February 2026, depending on working days; typically 7-10 days before the exam).
How to Download Admit Card 2026
- Visit the official UPSC portal:https://upsconline.nic.in
- Look for the link: “admit card: Combined Geo-Scientist (Preliminary) Examination, 2026”
- Log in using your credentials:
Universal Registration Number (URN) (generated during application).
Date of Birth (as entered in the application).
Captcha or other verification.
Download and print the admit card (PDF format). No physical admit card is sent by post.
Carry a printed copy along with the original Photo ID (Aadhaar/Voter/PAN/Passport/Driving Licence/etc.) whose details were provided during application. The same ID must be used throughout (Prelims, Mains, Interview).
Important Instructions from the Notification
Provide a valid active email ID during account creation — UPSC may send notifications/updates electronically.
Check details on the admit card carefully (name, roll number, centre, photo, etc.). Report any discrepancies immediately via email to UPSC (e.g., usgeol-upsc@nic.in for applicant data issues or system-upsc@gov.in for technical problems).
Reach the exam venue at least 30 minutes before the session starts — no late entry allowed.
Mobile phones/electronic devices are strictly banned (even switched off); violation leads to disqualification and future bans.
Admission is provisional — final eligibility verified later (after qualifying stages).
All centres (as listed earlier: Ahmedabad, Bengaluru, Bhopal, etc.) support PwBD candidates.
EXAM RESULT
The UPSC Combined Geo-Scientist (CGS) Result 2026 will be released on the official website upsc.gov.in in PDF format. Candidates can check their roll number to see their qualification status for the next stage of the selection process.
Step 1: Visit the Official UPSC Website
Go to the official UPSC result page: https://upsc.gov.in
Step 2: Go to the “What’s New” / Results Section
On the homepage, find and click the link that says:
“UPSC CGS 2026 Result / Combined Geo-Scientist Result”
Step 3: Open the Result PDF
A PDF file with the list of qualified candidates will open.
Step 4: Search Your Roll Number
Use Ctrl + F (Find) and enter your Roll Number to check your result quickly.
Step 5: Download & Save
Click Download to save the PDF to your device.
You can also print a copy for future reference.
Important Note
UPSC CGS results are usually released in PDF format.
Results show only the roll numbers of qualified candidates.
For the Mains stage results, the same process applies again when announced.
OVERVIEW
The Combined Geo-Scientist Examination, commonly known as CGS, is a national-level competitive examination conducted by the Union Public Service Commission (UPSC) under the Government of India. Through this examination, candidates are recruited for various technical posts in central government departments such as the Geological Survey of India (GSI) under the Ministry of Mines and the Central Water Board (CWB) under the Ministry of Jal Shakti, for Group ‘A’ and Group ‘B’ positions.
For the UPSC CGS 2026, the primary objective of the examination is to select qualified candidates for Category-I posts, including Geologist, Geophysicist, Chemist, and Junior Hydrologist under the Central Government. This examination serves as the entry-level gateway for aspirants seeking a professional career in geoscience and allied technical services through the Union Public Service Commission.
Particulars | Details |
Exam Full Name | Combined Geo-Scientist |
Conducting Authority | Union Public Service Commission |
Admission Purpose | To recruit various Group ‘A’ and Group ‘B’ scientific posts in earth sciences and related fields in the Government of India. |
Exam Level | National |
Application Mode | Offline |
Exam Date | 08 February 2026 |
Official Website |
SELECTION PROCESS
The UPSC Combined Geo-Scientist (CGS) Examination 2026 is a multi-stage recruitment process conducted by the Union Public Service Commission (UPSC) to fill Group ‘A’ and Group ‘B’ posts in the Geological Survey of India (GSI) under the Ministry of Mines and the Central Ground Water Board (CGWB) under the Ministry of Jal Shakti. It is strictly merit-based, with provisional admission at every stage subject to final verification of eligibility, documents, and medical fitness.
The process consists of three successive stages:
1. Stage I: Preliminary Examination
Nature: Objective-type screening test (OMR-based).
Date: 8th February 2026.
Papers: Two papers (total 400 marks):
Paper-I: General Studies (100 marks, 2 hours).
Paper-II: Subject-specific (Geology/Hydrogeology, Geophysics, or Chemistry; 300 marks, 2 hours).
Negative Marking: 1/3rd marks deducted for wrong answers.
Purpose: To shortlist candidates for the Main Examination. Marks from Prelims are counted toward deciding the final merit in some contexts, but primarily serve as a qualifier.
Shortlisting Ratio: Approximately 6-7 times the number of vacancies (to allow for the Main stage).
Outcome: Candidates qualifying the Prelims (based on cut-off decided by UPSC) are declared qualified and allowed to appear for the Main Examination. Results are published on upsc.gov.in.
2. Stage II: Main Examination
Nature: Descriptive/Conventional type (pen-paper).
Date: 20th & 21st June 2026.
Papers: Three papers (total 600 marks, 3 hours each), subject-specific (Geology, Geophysics, or Chemistry stream based on applied category).
Purpose: To assess in-depth knowledge and analytical skills. Marks from Mains are counted for the final merit.
Shortlisting for Interview: Candidates who secure minimum qualifying marks (as decided by UPSC) in the Mains are called for the Personality Test. The number shortlisted is typically based on vacancies and merit.
Outcome: Main results are declared, and qualified candidates proceed to the Interview stage.
3. Stage III: Personality Test / Interview
Marks: 200
Nature: Oral interview by a UPSC board (usually 20-30 minutes).
Purpose: To evaluate personality, suitability for geo-scientific roles, depth of subject knowledge, communication skills, awareness of current geo-scientific issues (e.g., mineral exploration, groundwater management, natural hazards), and general awareness.
No fixed syllabus: Questions draw from bio-data, Mains performance, and relevant current affairs.
Outcome: Marks are added to Mains for final merit.
Final Merit List and Allocation
Final Merit Calculation: Based on Mains (600 marks) + Personality Test (200 marks) = 800 marks total. Prelims marks may influence shortlisting, but are not added to the final merit list in standard practice (though notification notes they count for final merit in some aspects).
Merit Position: Candidates are ranked in order of merit within their category (General, SC/ST/OBC/EWS/PwBD, etc.).
Post Allocation:
Strictly according to merit position, number of vacancies, and preferences (candidates can apply for one or both categories — GSI or CGWB — in one application).
Separate merit lists for:
Category-I: Posts in GSI (Geologist, Geophysicist, Chemist Group ‘A’).
Category-II: Posts in CGWB (Scientist ‘B’ in Hydrogeology/Chemical/Geophysics Group ‘A’; Assistant Hydrogeologist/Chemist/Geophysicist Group ‘B’).
Selection is category-wise and vacancy-specific. Overlapping qualifications allow competition in both, but allocation follows merit and vacancies separately.
Reservation: Applied as per Government rules (SC/ST/OBC/EWS/PwBD/Ex-Servicemen). Reservations are category-specific and cannot be interchanged post-result except in rare documented cases.
Final Result: Declared by UPSC after Interview. Recommended candidates receive appointment letters from respective ministries (Mines for GSI, Jal Shakti for CGWB).
Steps After Merit List
Document Verification: Conducted after qualifying for Interview/Personality Test (or post-final result). Original documents (educational certificates, age proof, category certificates, photo ID, etc.) are verified. Provisional admission can be cancelled if discrepancies arise.
Medical Examination: Candidates must meet prescribed physical/medical standards (as per Rights of Persons with Disabilities Act, 2016, and cadre-specific Functional Classification/Physical Requirements). For PwBD candidates, disability must be ?40% and suitable for the post.
Appointment: On temporary basis initially. Final offer depends on clearance of all verifications and fitness. No withdrawal of application is allowed post-submission.
Key Notes
Admission at all stages is purely provisional; mere issue of admit card does not guarantee eligibility.
No request for category change (e.g., General to Reserved) is entertained after application, except exceptional cases (<3 months gap in community notification).
The process emphasizes merit, with strict adherence to rules notified in the Gazette of India (dated 03.09.2025).
For the most accurate and latest details (including any updates), refer to the official notification PDF on upsc.gov.in.
EXAM SYLLABUS
The UPSC Civil Services syllabus is distinct for the Prelims and Mains stages. With the UPSC 2026 Prelims exam date announced, aspirants should thoroughly review the complete syllabus and plan their preparation in a structured and focused manner.
The detailed syllabus of UPSC CGS Mains Examination is given below:-
Stream-I: Scientist ‘B’ (Hydrogeology)
| Name of Test | Topic | Weightage |
| Paper-I: Geology | Physical geology and remote sensing: Principle of uniformitarianism; origin, differentiation and internal structure of the Earth; origin of atmosphere; earthquakes and volcanoes; continental drift, etc. | 11 Q |
| Structural geology: Stress, strain and rheological properties of rocks; planar and linear structures; classification of folds and faults, etc. | ||
| Sedimentology: Origin of sediments; sedimentary textures, grain-size scale; primary sedimentary structures; classification of sandstone and carbonate rocks, etc. | ||
| Paleontology: Origin of sediments; sedimentary textures, grain-size scale; primary sedimentary structures; classification of sandstone and carbonate rocks, etc. | ||
| Stratigraphy: Law of superposition; stratigraphic nomenclature- lithostratigraphy, biostratigraphy and chronostratigraphy; Archaean cratonic nucleii of Peninsular India (Dharwar, Singhbhum, and Aravalli cratons); Proterozoic mobile belts, etc. | ||
| Paper-II: Geology | Mineralogy: Symmetry, motif, Miller indices; concept of unit cell and Bravais lattices; 32 crystal classes; types of bonding, Pauling’s rules and coordination polyhedra; crystal imperfections-defects, etc. | 11 Q |
| Geochemistry and isotope geology: Chemical composition and characteristics of atmosphere, lithosphere, hydrosphere; geochemical cycles; meteorites-types and composition; Goldschmidt’s classification of elements; fractionation of elements in minerals/rocks; Nernst’s partition coefficient (compatible and incompatible elements), etc. | ||
| Metamorphic petrology: Limits and physico-chemical controls (pressure, temperature, fluids and bulk rock composition) of metamorphism; concept of zones, facies, isograds and facies series, geothermal gradients and tectonics of orogenic belts; structures, micro-structures, etc. | ||
| Geodynamics: Phase transitions and seismic discontinuities in the Earth; seismic waves and relation between Vp, Vs and density; seismic and petrological Moho; rheology of rocks and fluids (Newtonian and nonNewtonian liquids); rock magnetism and its origin; polarity reversals, polar wandering and supercontinent cycles; continental drift, etc. | ||
| Igneous petrology Viscosity: temperature and pressure relationships in magmas; IUGS classification of plutonic and volcanic rocks; nucleation and growth of minerals in magmatic rocks, development of igneous textures; magmatic evolution (differentiation, assimilation, mixing and mingling); types of mantle melting (batch, fractional and dynamic); binary (albite-anorthite, forsterite-silica and diopsideanorthite) and ternary, etc. | ||
| Paper-III: Hydrogeology | Occurrence and distribution of groundwater: Origin of water on Earth; global water cycle and budget; residence time concept, geologic formations as aquifers; confined and unconfined aquifers, etc. | 09 Q |
| Groundwater movement and well hydraulics: Groundwater flow concepts; Darcy’s Law in isotropic and anisotropic media and validity; water flow rates, direction and water volume in aquifers, etc. | ||
| Water wells and groundwater levels: Unidirectional and radial flow to a well (steady and unsteady); well flow near aquifer boundaries; methods for constructing shallow wells, etc. | ||
| Groundwater exploration: Surface investigation of groundwater- geologic, remote sensing, electrical resistivity, seismic, gravity and magnetic methods; sub-surface investigation of groundwater, etc. | ||
| Groundwater quality and management: Groundwater composition, units of expression, mass-balance calculations; rock-water interaction (chemical equilibrium, free energy, redox reactions and cation/anion exchanges), graphic representation of chemical data; groundwater hardness, etc. |
Stream-II: Scientist ‘B’ (Geophysics)
| Name of Test | Topic | Weightage |
| Paper-I: Geophysics | Part A | 10 Q |
| Solid Earth Geophysics: Introduction to Geophysics and its branches. Solar system: origin, characteristics of planets, Earth: rotation and figure, Geoid, Spheroid and topography, etc. | ||
| Earthquake Seismology: Seismology, earthquakes, focal depth, epicenter, great Indian earthquakes, Intensity and Magnitude scales, Energy of earthquakes, foreshocks, etc. | ||
| Mathematical methods in Geophysics: Elements of vector analysis, Gradient, Divergence and Curl, Gauss’s divergence theorem, Stoke’s theorem, Gravitational field, Newton’s Law of gravitation, etc. | ||
| Geophysical Inversion: Fundamental concepts of inverse theory, Definition and its application to Geophysics. Probability, Inversion with discrete and continuous models. Forward problems versus Inverse problems, direct and model based inversions, Formulation of inverse problems, classification of inverse problems, least square solutions and minimum norm solution, etc. | ||
| Part B | ||
| Mathematical Methods of Physics: Dimensional analysis; Units and measurement; Vector algebra and vector calculus; Linear algebra, Matrices: Eigenvalues and eigenvectors, etc. | ||
| Electrodynamics: Electrostatics: Gauss’ Law and its applications; Laplace and Poisson equations, Boundary value problems; Magnetostatics: Biot-Savart law, etc. | ||
| Electromagnetic Theory: Maxwell’s equations: its differential and integral forms, physical significance; Displacement current; Boundary conditions; Wave equation, etc. | ||
| Introductory Atmospheric and Space Physics: The neutral atmosphere; Atmospheric nomenclature; Height profile of atmosphere; Hydrostatic equation; Geopotential height, etc. | ||
| Paper-II: Geophysics | Part A | 10 Q |
| Potential Field (Gravity and Magnetic) Methods: Geophysical potential fields, Inverse square law, Principles of Gravity and Magnetic methods, Global gravity anomalies, Newtonian and logarithmic potential, Laplace’s equations for potential field. Green’s Function, Concept of gravity anomaly, etc. | ||
| Electrical and Electromagnetic methods: Electrical properties of rocks and minerals, concepts and assumptions of horizontally stratified earth, anisotropy and its effects on electrical fields, geoelectric and geological sections, D.C Resistivity method, etc. | ||
| Seismic Prospecting: Basic principles of seismic methods, Various factors affecting seismic velocities in rocks, Reflection, refraction and Energy partitioning at an interface, Geometrical spreading, Reflection and refraction of wave phenomena in a layered and dipping media, etc. | ||
| Borehole Geophysics: Objectives of well logging, concepts of borehole geophysics, borehole conditions, properties of reservoir rock formations, formation parameters and their relationships-formation factor, porosity, permeability, formation water resistivity, water saturation, irreducible water saturation, hydrocarbon saturation, residual hydrocarbon, etc. | ||
| Part B | ||
| Classical Mechanics: Inertial and non-inertial frames, Newton’s laws; Pseudo forces; Central force motion; Two-body collisions, Scattering in laboratory and centre-of-mass frames, etc. | ||
| Thermodynamics and Statistical Physics :Laws of thermodynamics and their significance; Thermodynamic potentials, Maxwell relations; Chemical potential, Phase equilibria, etc. | ||
| Atomic and Molecular Physics and Characterization of materials: Quantum states of an electron in an atom; Electron spin; Stern-Gerlach experiment; Spectrum of Hydrogen, Helium and alkali atoms, etc. | ||
| Nuclear and Particle Physics: Basic nuclear properties: size, shape, charge distribution, spin and parity; Binding energy, Packing fraction, Semi-empirical mass formula, etc. | ||
| Paper-III: Geophysics | Part A | 10 Q |
| Radiometric and Airborne Geophysics: Principles of radioactivity, radioactivity decay processes, units, radioactivity of rocks and minerals, Instruments, Ionization chamber, etc. | ||
| Marine Geophysics: Salinity, temperature and density of sea water. Introduction to Sea-floor features: Physiography, divisions of sea floor, etc. | ||
| Geophysical Signal Processing: Time Series, Types of signals, sampling theorem, aliasing effect, Fourier series of periodic waveforms, Fourier transform and its properties, etc. | ||
| Remote Sensing and Geohydrology: Fundamental concepts of remote sensing, electromagnetic radiation spectrum, Interaction of electromagnetic energy and its interactions in atmosphere and surface of the earth, elements of photographic systems, etc. | ||
| Part B | ||
| Solid State Physics and Basic Electronics: Crystalline and amorphous structure of matter; Different crystal systems, Space groups; Methods of determination of crystal structure, etc. | ||
| Laser systems: Spontaneous and stimulated emission of radiation. Coherence, Light amplification and relation between Einstein A and B coefficients, etc. | ||
| Digital electronics, Radar systems, Satellite communications: Digital techniques and applications: Boolean identities, de Morgan’s theorems, Logic gates and truth tables; Simple logic circuits: registers, etc. | ||
| Quantum Mechanics: Wave-particle duality; Wave functions in coordinate and momentum representations; Commutators and Heisenberg’s uncertainty principle, etc. |
Stream-III: Chemist & Scientist ‘B’ (Chemical)
| Name of Test | Topic | Weightage |
| Paper-I: Chemistry | Inorganic solids: Defects, non-stoichiometric compounds and solid solutions, atom and ion diffusion, solid electrolytes. Synthesis of materials, etc. | 11 Q |
| Chemistry of coordination compounds: Determination of configuration of cis- and trans- isomers by chemical methods. Labile and inert complexes, etc. | ||
| Acid-base titrations: Elementary Crystal Field Theory: splitting of dn configurations in octahedral, square planar and tetrahedral fields, etc. | ||
| Gravimetric Analysis: Titration curves for strong acid-strong base, weak acid-strong base and weak base-strong acid titrations, polyprotic acids, etc. | ||
| Redox Titrations: Standard redox potentials, Nernst equation. Influence of complex formation, precipitation and change of pH on redox potentials, etc. | ||
| Complexometric titrations: Complex formation reactions, stability of complexes, stepwise formation constants, chelating agents. EDTA, etc. | ||
| Nuclear chemistry: Radioactive decay- General characteristics, decay kinetics, parent-daughter decay growth relationships, determination of half-lives. Nuclear stability, etc. | ||
| Chemistry of d- and f-block elements: d-block elements: General comparison of 3d, 4d and 5d elements in terms of electronic configuration, elemental forms, metallic nature, atomization energy, oxidation states, redox properties, coordination chemistry, spectral and magnetic properties. f-block elements: Electronic configuration, ionization enthalpies, oxidation states, variation in atomic and ionic (3+) radii, magnetic and spectral properties of lanthanides, separation of lanthanides (by ion-exchange method), etc. | ||
| Paper-II: Chemistry | Kinetic theory and the gaseous state: Real gases, Deviation of gases from ideal behaviour; compressibility factor; van der Waals equation of state and its characteristic features, etc. | 15 Q |
| Solids: Nature of solid state. Band theory of solids, etc. | ||
| Chemical thermodynamics and chemical equilibrium: Chemical potential in terms of Gibbs energy and other thermodynamic state functions and its variation with temperature and pressure, etc. | ||
| Chemical kinetics and catalysis: Second order reactions. Determination of order of reactions. Parallel and consecutive reactions. Temperature dependence of reaction rate, energy of activation. Collision Theory and Transition State Theory of reaction rates. Enthalpy of activation, entropy of activation, etc. | ||
| Electrochemistry: Types of electrochemical cells, cell reactions, emf and Nernst equation, ?G, ?H and ?S of cell reactions, etc. | ||
| Quantum chemistry: Eigenfunctions and eigenvalues. Uncertainty relation, Expectation value, etc. | ||
| Basic principles and applications of spectroscopy: Electromagnetic radiation, interaction with atoms and molecules and quantization of different forms of energies. Units of frequency, etc. | ||
| Photochemistry: Franck-Condon principle and vibrational structure of electronic spectra. Bond dissociation and principle of determination of dissociation energy, etc. | ||
| Paper-III: Chemistry | Part A | 10 Q |
| Errors in quantitative analysis: Accuracy and precision, sensitivity, specific standard deviation in analysis, classification of errors and their minimization, etc. | ||
| Separation Methods: Basic principles of chromatography (partition, adsorption and ion exchange), column chromatography, plate concept, etc. | ||
| Spectroscopic methods of analysis: Lambert-Beer’s Law and its limitations. UV-Visible Spectroscopy: Basic principles of UV-Vis spectrophotometer, Instrumentation consisting of source, monochromator, grating and detector, etc. | ||
| Thermal methods of analysis: Theory of thermogravimetry (TG), basic principle of instrumentation, techniques for quantitative analysis of Ca and Mg compounds, etc. | ||
| X-ray methods of Analysis: Introduction, theory of X-ray generation, X-ray spectroscopy, X-ray diffraction and X-ray fluorescence methods, etc. | ||
| Inductively coupled plasma spectroscopy: Theory and principles, plasma generation, utility of peristaltic pump, sampler–skimmer systems, ion lens, quadrupole mass analyzer, etc. | ||
| Analysis of geological materials: Analysis of minerals and ores- estimation of (i) CaCO3, MgCO3 in dolomite (ii) Fe2O3, Al2O3, and TiO2 in bauxite (iii) MnO and MnO2 in pyrolusite, etc. | ||
| Part B | ||
| Unstable, uncharged intermediates: Structure and reactivity of carbenes and nitrenes and their rearrangements (Reimer-Tiemann, Hoffman, Curtius, Lossen, and Schimdt,), etc. | ||
| Addition reactions: Mechanism of addition involving electrophiles, nucleophiles and free radicals (polymerization reactions of alkenes, etc. | ||
| Reactions at the carbonyl group: Cannizzaro, Aldol, Perkin, Claisen ester, benzoin, benzil-benzilic, etc. | ||
| Oxidation and Reduction: Reduction of C=C, Meerwein-Pondorf reaction, Wolff-Kishner and Birch reduction. Oxidation of C=C, etc. | ||
| Electro cyclic Reactions: Molecular orbital symmetry, frontier orbitals of ethylene, 1,3-butadiene, 1,3,5-hexatriene, allyl system, etc. | ||
| Spectroscopic methods of analysis: Characteristic frequencies of organic molecules and interpretation of spectra. Modes of molecular vibrations, characteristic stretching frequencies of O-H, N-H, C-H, C-D, C=C, C=N, C=O functions; factors affecting stretching frequencies, etc. |
EXAM PATTERN
The Mains Examination for UPSC Geo-Scientist shall be held as a Descriptive Type Test. The mains examination is divided into three Papers in each stream each paper containing 200 marks. The maximum marks for each stream is 600 for which a time of 3 hours will be provided for each Paper.
Stream-I: Scientist ‘B’ (Hydrogeology)
| Test Mode | Name of Test | Maximum Marks | Duration |
| Descriptive Type Offline Pen & Paper Based Test | Paper-I: Geology | 200 Marks | 180 Minutes |
| Paper-II: Geology | 200 Marks | 180 Minutes | |
| Paper-III: Hydrogeology | 200 Marks | 180 Minutes | |
| Total | 600 Marks | 540 Minutes |
Stream-II: Scientist ‘B’ (Geophysics)
| Test Mode | Name of Test | Maximum Marks | Duration |
| Descriptive Type Offline Pen & Paper Based Test | Paper-I: Geophysics | 200 Marks | 180 Minutes |
| Paper-II: Geophysics | 200 Marks | 180 Minutes | |
| Paper-III: Geophysics | 200 Marks | 180 Minutes | |
| Total | 600 Marks | 540 Minutes |
Stream-III: Chemist & Scientist ‘B’ (Chemical)
| Test Mode | Name of Test | Maximum Marks | Duration |
| Descriptive Type Offline Pen & Paper Based Test | Paper-I: Chemistry | 200 Marks | 180 Minutes |
| Paper-II: Chemistry | 200 Marks | 180 Minutes | |
| Paper-III: Chemistry | 200 Marks | 180 Minutes | |
| Total | 600 Marks | 540 Minutes |
Mod of Examination
The mains examination will contain three Conventional type papers. The papers will be Descriptive in nature and will be held through offline mode.
Medium of Examination
Conventional type papers must be answered in English only. Question paper will be set in English only.
Marking Scheme
There will be no negative marking in conventional type papers.
Personality Test / Interview
1. Stage III will consist of Personality Test/Interview carrying 200 Marks (with no minimum qualifying marks).
2. Candidates, who obtain such minimum qualifying marks in Stage II as may be fixed by the Commission as per its discretion, shall be summoned for Stage III (Personality Test).
3. The number of candidates to be summoned for the Personality Test will be about twice the number of vacancies to be filled.
4. In the Personality Test, the candidate will be interviewed by Board i.e. Interview Board (s) constituted by the Commission. The object of the interview will be to assess the suitability for the post(s) of Chemist, Scientist ‘B’(Hydrogeology), Scientist ‘B’(Chemical), and Scientist ‘B’ (Geophysics).
5. Special attention will be paid in the Personality Test to assess the candidate’s capacity for leadership, initiative, and intellectual curiosity, tact and other social qualities, mental and physical energy powers of practical application, the integrity of character, and aptitude for adapting themselves to the field life.
ELIGIBILITY CRITERIA
Candidates willing to apply for UPSC Combined Geo-Scientist are required to fulfil certain conditions to be eligible for it. The candidate who does not satisfy the Eligibility criteria like Age, Minimum educational qualification etc., their candidature shall be rejected by the authorities. The criteria for eligibility UPSC Combined Geo-Scientist are decided by the conduction body itself. The candidate’s eligibility for UPSC Combined Geo-Scientist Examination is based on the fulfilment of the following conditions:-
1. Nationality
2. Age Limit & Relaxations
3. Educational Qualifications
Nationality
A candidate must be either:
1. A citizen of India or
2. A subject of Nepal or A subject of Bhutan or
3. A Tibetan refugee who came to India before the 1st of January 1962 with the intention of permanently settling in India or
4. A person of Indian origin who has migrated from Pakistan, Burma, Sri Lanka, or East African countries of Kenya, Uganda, the United Republic of Tanzania, Zambia, Malawi, Zaire, and Ethiopia or from Vietnam with the intention of permanently settling in India.
Provided that a candidate belongs to categories (2), (3) and (4) above shall be a person in whose favor a certificate of eligibility has been issued by the Government of India.
Age Limits (as on January 1, 2026)
Minimum: 21 years (born not earlier than January 2, 1994).
Maximum: 32 years (born not later than January 1, 2005).
Candidates must meet the age criteria specifically for the posts they apply for (e.g., Group ‘A’ vs. Group ‘B’).
Age Relaxations
For government servants
The upper age limit will be relaxable upto a maximum of 7 years in the case of Government servants, if they are employed in a Department mentioned in Column I below and apply for the corresponding post mentioned in column II.
| Column I | Column II |
| Geological Survey of India | (i) Geologist Group ‘A’ (ii)Geophysicist Group ‘A (iii) Chemist Group ‘A’ |
| Central Ground Water Board | (i) Scientist ‘B’ (Hydrogeology) Group ‘A’. |
| (ii) Scientist ‘B’ (Hydrogeology) Group ‘A’. | |
| (iii)Scientist ‘B’ (Geophysics) Group ‘A’. |
Further Relaxations
| Categories | Age Relaxation |
| SC/ST | 5 Years |
| OBC | 3 Years |
| Defence Services Personnel disabled in operations during hostilities with any foreign country or in a disturbed area and released as a consequence thereof | 3 Years |
| Ex-servicemen including Commissioned Officers and ECOs/SSCOs who have rendered at least five years Military Service | 5 Years |
| Visually challenged/hearing impaired/physically challenged candidates | 10 Years |
Education Qualification
1. For Geologist Group ‘A’ in Geological Survey of India: Master’s degree in Geological Science or Geology or Applied Geology or Geo- Exploration or Mineral Exploration or Engineering Geology or Marine Geology or Earth Science and Resource Management or Oceanography and Coastal Areas Studies or Petroleum Geosciences or Geochemistry from a University incorporated by an Act of the Central or State Legislature in India or an educational institution established by an Act of Parliament or declared to be deemed university under section 3 of the University Grants Commission Act, 1956 (3 of 1956) i.e. recognized University.
2. For Geophysicist Group ‘A’ in Geological Survey of India and Scientist ‘B’ (Geophysics) Group ‘A’ in C.G.W.B.: M.Sc. in Physics or Applied Physics or M.Sc. (Geophysics) or Integrated M.Sc. (Exploration Geophysics) or M.Sc (Applied Geophysics) or M.Sc. (Marine Geophysics) or M.Sc. (Tech.) (Applied Geophysics) from a University incorporated by an Act of Parliament or State Legislature in India or other educational institutes established by an Act of the Parliament or declared to be deemed universities under the University Grants Commission Act, 1956
3. For Chemist Group ‘A’ in Geological Survey of India and Scientist ‘B’ (Chemical) under C.G.W.B.: M. Sc. in Chemistry or Applied Chemistry or Analytical Chemistry from a University incorporated by an Act of Parliament or State Legislature or other educational Institutes established by an Act of the Parliament or declared to be deemed Universities under section 3 of the University Grants Commission Act, 1956 i.e. recognized University.
4. For Scientist ‘B’ (Hydrogeology) Group ‘A’ and Assistant (Hydrogeologist) Group ‘B’ in C.G.W.B.: Master’s degree in Geology or applied Geology or Marine Geology or Hydrogeology from a University incorporated by an Act of the Central or State Legislature in India or other educational Institutes established by an act of Parliament or declared to be deemed as Universities under Section 3 of the University Grants Commission Act, 1956.
5. For Assistant (Chemist) Group ‘B’ in C.G.W.B.: Master of Science or Integrated Master of Science in Chemistry or Applied Chemistry or Analytical Chemistry or Physical Chemistry or Inorganic Chemistry or Organic Chemistry or Hydro-Chemistry or Industrial Chemistry from a recognized university or institute.
Notes
Candidates with overlapping qualifications (e.g., Geology for both GSI Geologist and CGWB Scientist ‘B’ Hydrogeology) can apply for both categories in one application (no extra fee).
No minimum percentage/marks is specified in the degree — only possession of the qualifying degree is required.
Physical/medical fitness is required per the Rights of Persons with Disabilities Act, 2016, and cadre-specific standards (Functional Classification and Physical Requirements detailed in the full rules).
Other Key Conditions
Candidates must possess valid certificates for reservations/relaxations (SC/ST/OBC/EWS/PwBD/Ex-Servicemen) by the application closing date (23.09.2025).
For EWS: Income & Asset Certificate for FY 2024-2025, issued on/after 01.04.2025 but not later than 23.09.2025.
For OBC (Non-Creamy Layer): Certificate based on income for FY 2022-2023, 2023-2024, 2024-2025, issued on/after 01.04.2025.
No changes in category (e.g., General to Reserved) are allowed after application submission (except rare cases with gap <3 months in community notification).
PwBD sub-category changes are not permitted.
Full details (including appendices on plan of exam, physical requirements) are in the official notification on upsc.gov.in
IMPORTANT DATES
The important dates for the UPSC Combined Geo-Scientist (CGS) Examination 2026 (as per the official notification No. 01/2026-GEOL dated 03.09.2025 and consistent updates from UPSC sources) are as follows. These are fixed unless changed by UPSC (check upsc.gov.in for any updates).
Events | Date |
UPSC CGS Notification 2024 | 03/09/2025 |
Online Registration Starts | 04/09/2025 |
Last Date to Apply Online | 23/09/2025 |
UPSC CGS Prelims Exam Date | 08/02/2026 |
UPSC CGS Mains Exam Date | 20/06/2026 |