India · IITs and IISc on rotation (2026: IIT Guwahati) · pg
1085practice questions written to this syllabus
36subjects
Format
Computer-based, 3 hours, 100 marks (15 General Aptitude + 85 subject). MCQ, MSQ and NAT question types with negative marking on MCQ only, as in all GATE papers.
Sections
General Aptitude (15 marks)
Section 1: Mathematics Foundation (linear algebra, calculus, ODEs, probability and statistics, regression, hypothesis tests)
Section 2: Environmental Chemistry (water, soil and atmospheric chemistry)
Section 4: Water Resources and Environmental Hydraulics
Section 5: Water & Wastewater Treatment and Management (including reactor kinetics, CETP, ZLD)
Section 6: Air and Noise Pollution
Section 7: Solid and Hazardous Waste Management
Section 8: Global and Regional Environmental Issues (GHGs, climate change, ecology, biodiversity)
Section 9: Environmental Management and Sustainable Development (EMS, ISO 14000, EIA, LCA, health risk assessment, Indian environmental law, energy, SDGs)
Over the years
The nine-section syllabus was read in full from the official 2026 PDF. GATE ES was introduced in GATE 2022, so at most five papers exist (2022–2026); Laisha has not yet counted marks per section and no official section weights are published. The general GATE format (3 hours, 65 questions, 100 marks, 15 GA) is the standard GATE pattern and was not re-read on this page. Used for M.Tech/M.E. environmental engineering and science admission, some PhD admission and some PSU screening.
Original questions written to this exam's published syllabus and pattern. Not past papers.
1. Fifty fish are marked and released. A later sample of 60 fish contains 10 marked fish. Using the Lincoln–Petersen method, what is the estimated population?
3000
120
300
500
Answer and working
C. 300
N = M × C ÷ R = 50 × 60 ÷ 10 = 300. 120 adds and doubles; 500 uses 50 × 10; 3000 omits division by R.
Ecology & Ecosystem Science · Population characteristics: density, natality, mortality, age structure
2. A water sample contains 40 mg/L of calcium (Ca²⁺, atomic mass 40). What is this expressed as mg/L as CaCO3?
40 mg/L as CaCO3
100 mg/L as CaCO3
200 mg/L as CaCO3
50 mg/L as CaCO3
Answer and working
B. 100 mg/L as CaCO3
Equivalent weight of Ca²⁺ = 40/2 = 20; mg/L as CaCO3 = 40 × 50/20 = 100. 40 forgets conversion; 50 uses the CaCO3 equivalent weight alone; 200 uses the molar mass of CaCO3 over 20.
Environmental Chemistry · Chemical bonding, concentration units, activity and ionic strength
3. Carl Woese's ribosomal RNA studies divided life into which three domains?
Plants, Animals and Fungi
Prokaryotes, Eukaryotes and Viruses
Bacteria, Archaea and Eukarya
Monera, Protista and Fungi
Answer and working
C. Bacteria, Archaea and Eukarya
Woese used 16S/18S rRNA to define Bacteria, Archaea and Eukarya; the others are older kingdom schemes or include viruses.
Environmental Microbiology · Prokaryotic and eukaryotic microorganisms; classification and diversity
4. The Great Oxidation Event, when oxygen began to accumulate in the atmosphere, occurred about:
240 million years ago
24,000 years ago
2.4 billion years ago
4.5 billion years ago
Answer and working
C. 2.4 billion years ago
Cyanobacterial photosynthesis eventually outpaced oxygen sinks such as reduced iron.
Earth Systems & Environmental Geoscience · Origin and evolution of the earth and its spheres
5. What is the determinant of the matrix [[3, 2], [1, 4]]?
−10
2
14
10
Answer and working
D. 10
det = 3 × 4 − 2 × 1 = 10. 14 adds the products; 2 and −10 are sign or order slips.
Mathematics & Statistics for Environmental Science · Linear algebra: matrices, linear systems, eigenvalues
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