NEET UG · Chemistry · Environmental Chemistry

Environmental Chemistry: NEET previous year questions

This topic’s chapter, Environmental Chemistry, is not in the NEET UG 2026 syllabus. It had 6 questions from 2017 to 2023; they are kept here for reference.

Asked in 10 years: 6; about 0.6 per paper
Years asked: 6/10; last asked 2023
Syllabus: Dropped; not in NEET UG 2026
Last asked: 2023; 3 papers ago

Key findings

01
Asked in 6 of 10 papers, 6 questions in all: #140 of 204 topics by ten-year total. It comes back every 1.2 years on average. Last asked in 2023.
02
100% of its questions since 2018 tested an idea never asked before; none repeated an idea from the year before.
03
No idea in this topic has been asked twice: every question tested something new.
04
NEET has asked 0 of the 6 ideas in this topic; 0 have never been asked, directly or indirectly.
05
Mostly asked as one-line MCQ (50%); 33% easy, 0% hard, and down from 0.8 to 0.0 questions a paper since 2024.

Questions per year

Up to 2023: 0.8; per paper
Since 2024: 0.0; -0.8
Usual gap: 1.2 yrs; between papers asking it
Swing: ±0.5; questions, year to year

How it is asked

Difficulty, format and skill

Across all 6 questions on Environmental Chemistry since 2017.

Difficulty

QUESTIONS

Easy2 · 33%
Medium4 · 67%
Hard0 · 0%

Format

One-line MCQ · 3 Q50%
Two statements · 1 Q17%
Other · 1 Q17%
Match the lists · 1 Q17%

Skill tested

Recall · 6 Q100%

Repeats

New idea, or one asked before?

Each column is a paper. Blue questions tested an idea NEET had not asked before; navy ones went back to an idea from an earlier paper. 2017 is the first paper, so everything in it counts as new.

’17’18’19’20’21’22’23’24’25’26

Idea asked for the first time
Idea asked in an earlier paper

Coverage of the topic

NEET has asked 0 of the 6 ideas in this topic. 0 have never been asked yet.

Asked directly0 · 0%
Touched inside another question6 · 100%
Never asked0 · 0%

Ideas come from Lumi’s syllabus map of NCERT. A never-asked idea is not a safe skip: most new questions come from exactly these.

Drill down

Idea, year, question

Every idea NEET tested in this topic, with its ten papers. Open one to read the questions.

ideaAskedShareYears’17’18’19’20’21’22’23’24’25’26

1 · 17%17%1/10
- 2017 · Q71
  Which of the following is a sink for CO ?
  mediumOne-line MCQNew idea
1 · 17%17%1/10
1 · 17%17%1/10
1 · 17%17%1/10
1 · 17%17%1/10
1 · 17%17%1/10

Squares are the ten papers, 2017 to 2026; darker means more questions. Share is of the level above.

Ideas

Every idea inside this topic

6 different ideas were tested; none came more than once.

Water Pollution and Eutrophication1×
statement i/ii on environmental pollution
Two statements · 4% next
SO2, Classical Smog and Particulates1×
identify factors enhancing pollution
Other · 4% next
Tropospheric and Stratospheric Reactions1×
match list on atmospheric pollution reactions
Match the lists · 4% next
Greenhouse Gases1×
odd-one-out among gases
One-line MCQ · 4% next
Oxides of Nitrogen as Pollutants1×
identify oxide not a pollutant
One-line MCQ · 4% next
Carbon Monoxide Sources and Sinks1×
identify sink of pollutant
One-line MCQ · 4% next

Idea	Times	Format	Chance next	Foundation for
Water Pollution and Eutrophicationstatement i/ii on environmental pollution	1	Two statementsRecall	4%	–
SO2, Classical Smog and Particulatesidentify factors enhancing pollution	1	OtherRecall	4%	–
Tropospheric and Stratospheric Reactionsmatch list on atmospheric pollution reactions	1	Match the listsRecall	4%	–
Greenhouse Gasesodd-one-out among gases	1	One-line MCQRecall	4%	–
Oxides of Nitrogen as Pollutantsidentify oxide not a pollutant	1	One-line MCQRecall	4%	–
Carbon Monoxide Sources and Sinksidentify sink of pollutant	1	One-line MCQRecall	4%	–

Chance next is the historical rate at which an idea with this record came back in the following paper. It is low for every idea, which is why learning the topic beats memorising past questions. All repeated ideas

Every question

Environmental Chemistry questions, year by year

The opening words of each question as it appeared in the official paper, with the idea it tested.

NEET 20231 question

Q90
Given below are two statements : Statement I : The nutrient deficient water bodies lead to eutrophication. Statement II : Eutrophication…
Idea: Water Pollution and Eutrophication
New ideaEasyTwo statements

NEET 20221 question

Q94
The pollution due to oxides of sulphur gets enhanced due to the presence of : (a) particulate matter (b) ozone (c) hydrocarbons (d)…
Idea: SO2, Classical Smog and Particulates
New ideaMediumOther

NEET 20211 question

Q86
Match List - I with List - II. List - I | List - II (a) $\mathrm{2SO_2(g) + O_2(g) \to 2SO_3(g)}$ | (i) Acid rain (b)…
Idea: Tropospheric and Stratospheric Reactions
New ideaMediumMatch the lists

NEET 20191 question

Q52
Among the following, the one that is not a green house gas is :
Idea: Greenhouse Gases
New ideaEasyOne-line MCQ

NEET 20181 question

Q59
Which oxide of nitrogen is not a common pollutant introduced into the atmosphere both due to natural and human activity ?
Idea: Oxides of Nitrogen as Pollutants
New ideaMediumOne-line MCQ

NEET 20171 question

Q71
Which of the following is a sink for CO ?
Idea: Carbon Monoxide Sources and Sinks
MediumOne-line MCQ

Questions from the official NEET UG papers published by NTA (CBSE before 2019). Topic and idea tags, counts and notes are Lumi’s.