The maximum prescribed concentration of copper in drinking water is ........ $ppm$.

Give the details of the different layers of the atmosphere and briefly describe the substances present in them.

How is excessive content of $CO_2$ responsible for global warming?

The chemical added to leaded petrol to prevent the deposition of lead in the combustion chamber is

The pollutants which come directly into the air from sources are called primary pollutants. Primary pollutants are sometimes converted into secondary pollutants. Which of the following belongs to secondary air pollutants?

The upper stratosphere,consisting of the ozone layer,protects us from the sun's radiation that falls in the wavelength region of