With reference to "Water Pollution", consider the following statements: 1. It is caused by the discharge of untreated sewage. 2. It prevents the spread of diseases like cholera. 3. It affects only surface water and not groundwater. Which of the statements given above is/are correct?

The correct option is (a). Explanation Water pollution refers to the contamination of water bodies, such as lakes, rivers, oceans, aquifers, and groundwater, usually resulting from human activities. It occurs when pollutants are introduced into these water bodies without adequate treatment to remove harmful compounds. Statement-wise Analysis - Statement 1 is Correct: The discharge of untreated or partially treated sewage into water bodies is a primary cause of water pollution. Sewage contains organic matter, pathogens, and nutrients that degrade water quality and deplete dissolved oxygen. - Statement 2 is Incorrect: Water pollution does not prevent diseases; rather, it is a major cause of the spread of waterborne diseases. Contaminated water acts as a vector for pathogens causing diseases such as cholera, typhoid, dysentery, and hepatitis. - Statement 3 is Incorrect: Water pollution affects both surface water and groundwater. Pollutants from surface sources, such as agricultural runoff (containing nitrates and pesticides) and industrial waste, can leach through the soil and contaminate underground aquifers. Key Takeaway Water pollution encompasses the contamination of both surface water and groundwater sources. It is driven by factors like sewage discharge and agricultural runoff, serving as a primary transmission route for waterborne diseases rather than preventing them.

NCERT Class 7 Environment & Ecology — Chapter 2: Wastewater story

mcqeasy

With reference to "Water Pollution", consider the following statements:

It is caused by the discharge of untreated sewage.
It prevents the spread of diseases like cholera.
It affects only surface water and not groundwater.

Which of the statements given above is/are correct?

Official previous-year question

Verified 1 Aug 2026.

Options

A1 only
B2 only
C1 and 3 only
D1, 2 and 3

Did you get this right?

Solution

The correct option is (a).

Explanation

Water pollution refers to the contamination of water bodies, such as lakes, rivers, oceans, aquifers, and groundwater, usually resulting from human activities. It occurs when pollutants are introduced into these water bodies without adequate treatment to remove harmful compounds.

Statement-wise Analysis

Statement 1 is Correct: The discharge of untreated or partially treated sewage into water bodies is a primary cause of water pollution. Sewage contains organic matter, pathogens, and nutrients that degrade water quality and deplete dissolved oxygen.
Statement 2 is Incorrect: Water pollution does not prevent diseases; rather, it is a major cause of the spread of waterborne diseases. Contaminated water acts as a vector for pathogens causing diseases such as cholera, typhoid, dysentery, and hepatitis.
Statement 3 is Incorrect: Water pollution affects both surface water and groundwater. Pollutants from surface sources, such as agricultural runoff (containing nitrates and pesticides) and industrial waste, can leach through the soil and contaminate underground aquifers.

Key Takeaway

Water pollution encompasses the contamination of both surface water and groundwater sources. It is driven by factors like sewage discharge and agricultural runoff, serving as a primary transmission route for waterborne diseases rather than preventing them.

Your note

More from Chapter 2: Wastewater story

With reference to the composition of sewage, consider the following statements: 1. It is a liquid waste consisting entirely of dissolved impurities. 2. It contains nutrients such as phosphorus and nitrogen. 3. It is devoid of any saprophytic or disease-causing bacteria. Which of the statements given above is/are correct?

medium

Consider the following statements regarding the impurities found in sewage: 1. Urea and pesticides are classified as organic impurities. 2. Nitrates and phosphates are classified as organic impurities. 3. Vegetable waste and animal waste are classified as organic impurities. Which of the statements given above is/are correct?

medium

Consider the following statements regarding the physical treatment of wastewater: 1. Bar screens are used to remove large objects like rags and sticks. 2. The speed of wastewater is increased in the grit and sand removal tank to facilitate filtration. 3. Sedimentation tanks are designed to increase the flow speed to prevent settling of solids. Which of the statements given above is/are correct?

medium

With reference to unit operations used in wastewater treatment, the role of a skimmer is to:

medium

Consider the following statements regarding "Activated Sludge": 1. It consists of suspended microbes that settle at the bottom of the tank after aeration. 2. It contains a very low percentage of water, being mostly solid. 3. A part of it is pumped back into the aeration tank to serve as an inoculum. Which of the statements given above is/are correct?

hard

Keep practising Chapter 2: Wastewater story

Work through every question from this NCERT chapter.

Browse all NCERT Class 7 Environment & Ecology chapters

The correct option is (a).

Explanation

Statement-wise Analysis

Statement 1 is Correct: The discharge of untreated or partially treated sewage into water bodies is a primary cause of water pollution. Sewage contains organic matter, pathogens, and nutrients that degrade water quality and deplete dissolved oxygen.
Statement 2 is Incorrect: Water pollution does not prevent diseases; rather, it is a major cause of the spread of waterborne diseases. Contaminated water acts as a vector for pathogens causing diseases such as cholera, typhoid, dysentery, and hepatitis.
Statement 3 is Incorrect: Water pollution affects both surface water and groundwater. Pollutants from surface sources, such as agricultural runoff (containing nitrates and pesticides) and industrial waste, can leach through the soil and contaminate underground aquifers.