$pH$ value for acid rain will be

In municipal sewage,$BOD$ values (in $ppm$) are

Name the pollutants found in the troposphere.

Explain the side effects of the use of herbicides on living things.

London smog is composed of which of the following?

Fill in the blanks:
$(1)$ Hydrocarbon compounds are made from ........ and ........ .
$(2)$ ........ has a capacity to stop the flow of oxygen.
$(3)$ ........ is formed by attaching carbon monoxide with hemoglobin in blood.