The gaseous envelope around the earth is known as the atmosphere. The lowest layer of this extends up to $10 \ km$ from sea level; this layer is $.......$

Formation of photochemical smog involves the following reactions in which $A$,$B$,and $C$ are respectively:
$(i)$ $NO_2 \stackrel{h\nu}{\longrightarrow} A + B$
$(ii)$ $B + O_2 \rightarrow C$
$(iii)$ $A + C \rightarrow NO_2 + O_2$
Choose the correct answer from the options given below:

Which gaseous pollutant,even in low concentrations,causes respiratory distress such as inflammation and irritation in the human respiratory tract?

During a school field trip,a botany student visited a beautiful pond in a village and collected some plants. He observed that villagers were washing clothes there,and household waste was spoiling its beauty in some areas. After a few years,he revisited the pond and found it completely covered with algae,emitting a foul smell,and the water had become unusable. Can you describe this condition of the pond?

Which of the following statements about the depletion of ozone layer is correct?

The pair of gases responsible for acid rain are