With reference to the river pollution, consider the following statements: 1. The Ganga water is able to dilute and assimilate pollution loads within 20 km of large cities given adequate streamflow. 2. Increasing urbanisation and industrialisation have not affected the self-cleansing capacity of the river. Which of the statements given above is/are correct?

The correct option is (a) 1 only. Explanation Rivers possess a natural self-cleansing capacity, wherein the flow of water helps dilute and assimilate organic and inorganic waste over a specific distance. This capacity relies heavily on the volume of streamflow and the quantity of pollutants discharged. - Statement 1 is Correct: The Ganga river naturally possesses the potential to dilute and assimilate pollution loads within approximately 20 km of large cities. This natural purification process functions effectively when there is adequate streamflow to disperse the contaminants. - Statement 2 is Incorrect: The increasing pressure of urbanization and industrialization has significantly affected the river's self-cleansing capacity. The extraction of large quantities of water for irrigation reduces the streamflow, while the discharge of untreated sewage and industrial effluents overwhelms the river's natural ability to purify itself. Consequently, the pollution load remains high, and the self-cleansing mechanism fails to operate effectively. Key Takeaway: While the Ganga has a theoretical potential to assimilate waste within 20 km given sufficient flow, anthropogenic factors such as reduced water volume and excessive pollutant discharge have largely nullified this self-cleansing capacity.

With reference to the river pollution, consider th... - NCERT Class 9 Geography MCQ

Solution

The correct option is (a) 1 only.

Explanation

Rivers possess a natural self-cleansing capacity, wherein the flow of water helps dilute and assimilate organic and inorganic waste over a specific distance. This capacity relies heavily on the volume of streamflow and the quantity of pollutants discharged.

Statement 1 is Correct: The Ganga river naturally possesses the potential to dilute and assimilate pollution loads within approximately 20 km of large cities. This natural purification process functions effectively when there is adequate streamflow to disperse the contaminants.
Statement 2 is Incorrect: The increasing pressure of urbanization and industrialization has significantly affected the river's self-cleansing capacity. The extraction of large quantities of water for irrigation reduces the streamflow, while the discharge of untreated sewage and industrial effluents overwhelms the river's natural ability to purify itself. Consequently, the pollution load remains high, and the self-cleansing mechanism fails to operate effectively.

Key Takeaway: While the Ganga has a theoretical potential to assimilate waste within 20 km given sufficient flow, anthropogenic factors such as reduced water volume and excessive pollutant discharge have largely nullified this self-cleansing capacity.

NCERT Class 9 Geography — Chapter 3: Drainage

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