Which of the following is not a conventional source of energy?

Which are the primary constituents of photochemical smog?

In a pond near a village,a large number of fish suddenly die. Which of the following could be the reason for this?
$(a)$ Large amounts of urea and phosphate are used as fertilizers in nearby fields.
$(b)$ $DDT$ was sprayed in the entire area.
$(c)$ The pond water has become green and dirty.
$(d)$ The population of phytoplankton in the pond has decreased,reducing the photosynthetic capacity.
Which two of the above reasons are responsible?

In the given pie chart,what do $W, X, Y$ and $Z$ represent respectively?

At the beginning of the $20^{th}$ century,forests covered about $.....P.....$ of the land in India. By the end of the century,this had shrunk to $.....Q.....$.

In Maharashtra,a $24$-hour toll-free helpline number $1926$ has been set up to provide information regarding . . . . . . .