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National Environmental Quality Standards (NEQS) (Environmental Sciences) Solved Questions & Notes (2026) - Apex Rankers

Environmental Sciences & Management > Environmental Sciences > National Environmental Quality Standards (NEQS)

50 Total Solved Questions
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National Environmental Quality Standards (NEQS)

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Q. 1 Environmental Sciences
Difficulty: Medium (1 Mark)
Under the National Environmental Quality Standards (NEQS) for Municipal and Liquid Industrial Effluents in Pakistan, what is the permissible limit for Biochemical Oxygen Demand (BOD5 at 20 °C) into inland waters?
A
80 mg/L
✓ Correct
B
200 mg/L
C
400 mg/L
D
10 mg/L
💡 Step-by-Step Explanation & Concept Rationale
The NEQS standard for BOD5 (at 20 °C) for discharge into inland waters is 80 mg/L (into sewage treatment it is 250 mg/L, into sea 80 mg/L).
Q. 2 Environmental Sciences
Difficulty: Medium (1 Mark)
Under NEQS for Municipal and Liquid Industrial Effluents, what is the permissible limit for Chemical Oxygen Demand (COD) into inland waters?
A
150 mg/L
✓ Correct
B
400 mg/L
C
80 mg/L
D
1000 mg/L
💡 Step-by-Step Explanation & Concept Rationale
The NEQS limit for Chemical Oxygen Demand (COD) into inland surface waters is 150 mg/L (400 mg/L into sea).
Q. 3 Environmental Sciences
Difficulty: Easy (1 Mark)
What is the permissible pH range for municipal and industrial wastewater effluents under Pakistan NEQS?
A
6 to 9
✓ Correct
B
1 to 4
C
7.0 only
D
9 to 14
💡 Step-by-Step Explanation & Concept Rationale
Pakistan NEQS specifies an acceptable effluent pH range of 6.0 to 9.0 for discharge into inland waters, sewage treatment, or the sea.
Q. 4 Environmental Sciences
Difficulty: Medium (1 Mark)
Under Pakistan NEQS for liquid effluents, what is the maximum permissible concentration of Total Suspended Solids (TSS) into inland waters?
A
200 mg/L
✓ Correct
B
50 mg/L
C
500 mg/L
D
1000 mg/L
💡 Step-by-Step Explanation & Concept Rationale
The NEQS maximum permissible limit for Total Suspended Solids (TSS) into inland waters is 200 mg/L.
Q. 5 Environmental Sciences
Difficulty: Medium (1 Mark)
Under Pakistan NEQS for liquid effluents, what is the maximum permissible limit for Total Dissolved Solids (TDS) into inland waters?
A
3,500 mg/L
✓ Correct
B
500 mg/L
C
10,000 mg/L
D
100 mg/L
💡 Step-by-Step Explanation & Concept Rationale
The maximum permissible concentration of Total Dissolved Solids (TDS) for discharge into inland waters is 3,500 mg/L.
Q. 6 Environmental Sciences
Difficulty: Medium (1 Mark)
What is the NEQS limit for Oil and Grease in industrial wastewater effluents discharged into inland waters?
A
10 mg/L
✓ Correct
B
50 mg/L
C
100 mg/L
D
0.1 mg/L
💡 Step-by-Step Explanation & Concept Rationale
Pakistan NEQS restricts Oil and Grease in liquid industrial effluents to a maximum of 10 mg/L.
Q. 7 Environmental Sciences
Difficulty: Hard (1 Mark)
Under Pakistan NEQS for liquid effluents, what is the permissible limit for highly toxic Total Mercury (Hg)?
A
0.01 mg/L
✓ Correct
B
1.0 mg/L
C
5.0 mg/L
D
0.5 mg/L
💡 Step-by-Step Explanation & Concept Rationale
Because of mercury's bioaccumulative toxicity, the NEQS limit for Total Mercury is strictly set at 0.01 mg/L.
Q. 8 Environmental Sciences
Difficulty: Hard (1 Mark)
What is the Pakistan NEQS limit for Total Lead (Pb) in liquid industrial effluents?
A
0.5 mg/L
✓ Correct
B
5.0 mg/L
C
10.0 mg/L
D
0.001 mg/L
💡 Step-by-Step Explanation & Concept Rationale
The NEQS maximum concentration for Lead (Pb) in liquid effluent discharge is 0.5 mg/L.
Q. 9 Environmental Sciences
Difficulty: Hard (1 Mark)
What is the Pakistan NEQS limit for Total Cadmium (Cd) in liquid effluents?
A
0.1 mg/L
✓ Correct
B
1.0 mg/L
C
5.0 mg/L
D
10.0 mg/L
💡 Step-by-Step Explanation & Concept Rationale
Cadmium is an extremely toxic heavy metal (causing Itai-Itai disease); its NEQS limit in liquid effluent is 0.1 mg/L.
Q. 10 Environmental Sciences
Difficulty: Hard (1 Mark)
What is the Pakistan NEQS limit for Total Arsenic (As) in liquid industrial effluents discharged into inland waters?
A
0.1 mg/L (or 100 ppb)
✓ Correct
B
2.0 mg/L
C
10.0 mg/L
D
0.001 mg/L
💡 Step-by-Step Explanation & Concept Rationale
The NEQS limit for Total Arsenic in liquid effluent into inland waters is 0.1 mg/L.
Q. 11 Environmental Sciences
Difficulty: Medium (1 Mark)
What is the Pakistan NEQS limit for Total Chromium (Cr) in industrial wastewater discharges (common in tannery effluents in Kasur and Sialkot)?
A
1.0 mg/L
✓ Correct
B
10.0 mg/L
C
0.01 mg/L
D
50.0 mg/L
💡 Step-by-Step Explanation & Concept Rationale
The NEQS standard for Total Chromium (frequently used in chrome tanning) is 1.0 mg/L.
Q. 12 Environmental Sciences
Difficulty: Hard (1 Mark)
What is the Pakistan NEQS limit for Phenolic compounds (as phenol) in liquid effluent discharge?
A
0.1 mg/L
✓ Correct
B
5.0 mg/L
C
10.0 mg/L
D
50.0 mg/L
💡 Step-by-Step Explanation & Concept Rationale
Phenols produce objectionable tastes and odors in chlorinated water even at minute levels; the NEQS effluent limit is 0.1 mg/L.
Q. 13 Environmental Sciences
Difficulty: Medium (1 Mark)
Under Pakistan National Environmental Quality Standards for Ambient Air, what is the 24-hour permissible standard for Particulate Matter PM2.5?
A
35 micrograms per cubic meter (ug/m³)
✓ Correct
B
150 ug/m³
C
500 ug/m³
D
5 ug/m³
💡 Step-by-Step Explanation & Concept Rationale
The Pakistan Ambient Air Quality NEQS specifies a 24-hour average limit of 35 ug/m³ for PM2.5 (annual mean 15 ug/m³).
Q. 14 Environmental Sciences
Difficulty: Medium (1 Mark)
Under Pakistan Ambient Air Quality Standards, what is the 24-hour permissible standard for Particulate Matter PM10?
A
150 ug/m³
✓ Correct
B
35 ug/m³
C
500 ug/m³
D
50 ug/m³
💡 Step-by-Step Explanation & Concept Rationale
The NEQS 24-hour ambient air standard for PM10 is 150 ug/m³ (annual mean 120 ug/m³).
Q. 15 Environmental Sciences
Difficulty: Hard (1 Mark)
Under Pakistan NEQS for Industrial Gaseous Emissions, what is the general maximum permissible limit for Particulate Matter (PM)?
A
500 mg/Nm³
✓ Correct
B
50 mg/Nm³
C
1500 mg/Nm³
D
10 mg/Nm³
💡 Step-by-Step Explanation & Concept Rationale
For industrial boilers and furnaces, the general NEQS standard for particulate matter in gaseous emissions is 500 mg/Nm³ (milligrams per normal cubic meter).
Q. 16 Environmental Sciences
Difficulty: Medium (1 Mark)
What scale is specified in the Pakistan NEQS for evaluating the opacity or density of industrial smoke emissions?
A
Ringelmann Scale (Smoke opacity shall not exceed Ringelmann No. 2 or 40%)
✓ Correct
B
Beaufort Scale
C
Mohs Scale
D
Richter Scale
💡 Step-by-Step Explanation & Concept Rationale
Pakistan NEQS evaluates industrial smoke using the Ringelmann chart: emissions must not exceed Ringelmann Scale No. 2 (corresponding to 40% opacity).
Q. 17 Environmental Sciences
Difficulty: Hard (1 Mark)
Under Pakistan NEQS for Industrial Gaseous Emissions, what is the maximum permissible emission of Carbon Monoxide (CO)?
A
800 mg/Nm³
✓ Correct
B
100 mg/Nm³
C
5000 mg/Nm³
D
10 mg/Nm³
💡 Step-by-Step Explanation & Concept Rationale
The NEQS limit for Carbon Monoxide (CO) in industrial stack emissions is 800 mg/Nm³.
Q. 18 Environmental Sciences
Difficulty: Easy (1 Mark)
Under Pakistan Drinking Water Quality Standards, what is the bacteriological requirement for E. coli or total coliform bacteria in all treated water intended for drinking?
A
Must be 0 (zero) per 100 mL sample
✓ Correct
B
Up to 10 organisms per 100 mL
C
Up to 50 organisms per 100 mL
D
Up to 100 organisms per 100 mL
💡 Step-by-Step Explanation & Concept Rationale
Both WHO guidelines and Pakistan Drinking Water NEQS require that E. coli or thermotolerant coliform bacteria must not be detectable (0 count per 100 mL) in drinking water.
Q. 19 Environmental Sciences
Difficulty: Medium (1 Mark)
What is the Pakistan National Standard for Drinking Water Quality for Total Dissolved Solids (TDS)?
A
< 1,000 mg/L
✓ Correct
B
< 3,500 mg/L
C
< 100 mg/L
D
< 10 mg/L
💡 Step-by-Step Explanation & Concept Rationale
Pakistan standards recommend TDS in drinking water to be less than 1,000 mg/L (palatable and safe).
Q. 20 Environmental Sciences
Difficulty: Medium (1 Mark)
What is the Pakistan National Standard for Drinking Water Quality for Turbidity?
A
< 5 NTU (Nephelometric Turbidity Units)
✓ Correct
B
< 50 NTU
C
< 100 NTU
D
< 1 NTU only
💡 Step-by-Step Explanation & Concept Rationale
The Pakistan drinking water standard for turbidity is < 5 NTU.
Q. 21 Environmental Sciences
Difficulty: Hard (1 Mark)
What is the Pakistan National Standard for Arsenic in drinking water (historically adapted from regional standards)?
A
<= 50 ug/L (or 0.05 mg/L / 50 ppb)
✓ Correct
B
<= 1000 ug/L
C
<= 500 ug/L
D
0 ug/L exactly
💡 Step-by-Step Explanation & Concept Rationale
While the WHO provisional guideline for Arsenic in drinking water is 10 ug/L (10 ppb), the national standard in Pakistan NEQS has been set at <= 50 ug/L (50 ppb).
Q. 22 Environmental Sciences
Difficulty: Medium (1 Mark)
Under Pakistan NEQS for Motor Vehicle Exhaust and Noise, what is the maximum permissible noise level for motor vehicles at a distance of 7.5 meters?
A
85 dB(A)
✓ Correct
B
60 dB(A)
C
120 dB(A)
D
40 dB(A)
💡 Step-by-Step Explanation & Concept Rationale
The maximum permissible noise level for motor vehicles under NEQS is 85 dB(A) measured at a distance of 7.5 meters.
Q. 23 Environmental Sciences
Difficulty: Hard (1 Mark)
Under Pakistan NEQS for Ambient Noise, what is the daytime noise limit in designated 'Silence Zones' (areas within 100 meters around hospitals, educational institutions, and courts)?
A
50 dB(A)
✓ Correct
B
65 dB(A)
C
75 dB(A)
D
30 dB(A)
💡 Step-by-Step Explanation & Concept Rationale
In silence zones, NEQS specifies a daytime limit of 50 dB(A) and a nighttime limit of 45 dB(A).
Q. 24 Environmental Sciences
Difficulty: Medium (1 Mark)
Under Pakistan NEQS for Ambient Noise, what is the daytime limit in 'Residential Zones'?
A
55 dB(A)
✓ Correct
B
75 dB(A)
C
85 dB(A)
D
40 dB(A)
💡 Step-by-Step Explanation & Concept Rationale
The NEQS ambient noise limit for residential areas is 55 dB(A) during the day (06:00 to 22:00) and 45 dB(A) at night (22:00 to 06:00).
Q. 25 Environmental Sciences
Difficulty: Medium (1 Mark)
Under Pakistan NEQS for Ambient Noise, what is the daytime limit in 'Industrial Zones'?
A
75 dB(A)
✓ Correct
B
55 dB(A)
C
100 dB(A)
D
45 dB(A)
💡 Step-by-Step Explanation & Concept Rationale
In industrial areas, the NEQS permissible ambient noise limit is 75 dB(A) during the day and 65 dB(A) at night.
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