The quantity of $CO_2$ in the atmosphere is about (in $\%$)

List all the wastes that you generate at home,school,or during your trips to other places. Which could you very easily reduce? Which would be difficult or rather impossible to reduce?

Among the $X$ most polluted cities in the world,Delhi ranked at $Y$ position. Identify $X$ and $Y$.

All statements regarding $BOD$ (Biochemical Oxygen Demand) are correct,except:

According to the Forestry Commission Report $1997$,the total forest cover of India is ....... (in $\%$)

Which of the following is $NOT$ a bioindicator of water pollution?