When the biosphere becomes an environment useful to humans,what is it called?

Define environmental chemistry.

Given below are two statements:
Statement $I$: Non-biodegradable wastes are generated by the thermal power plants.
Statement $II$: Bio-degradable detergents lead to eutrophication.
In the light of the above statements,choose the most appropriate answer from the options given below:

The main cause of air pollution in large cities is ........

The acids responsible for acid rain are ......... .

How is ozone gas produced in the stratosphere?