QUESTION
Easy
Environment & Ecology
Prelims 2017
Biological Oxygen Demand (BOD) is a standard criterion for -
Select an option to attempt
Trusted by 2L aspirants
Practice UPSC Prelims PYQs Smarter

- Track accuracy & weak areas
- See past trends & repeated themes
Crack UPSC with your
Personal AI Mentor
An AI-powered ecosystem to learn, practice, and evaluate with discipline
