# Water sample is called cleanest on the basis of which one of the BOD values given below

Question:

Water sample is called cleanest on the basis of which one of the BOD values given below

1. $11 \mathrm{ppm}$

2. $15 \mathrm{ppm}$

3. 3 ppm

4. $21 \mathrm{ppm}$

Correct Option: , 3

Solution:

Clean water could have BOD value of less than $5 \mathrm{ppm}$ whereas highly polluted water could have a BOD value of $17 \mathrm{ppm}$ or more.