Carbon monoxide is the most dangerous when inhaled as it can lead to significant toxicity to the central nervous system and heart and can even cause death.

Sulphur dioxide produced in thermal power plants can permanently damage the lungs of the workers.

Nutrients added to water cause eutrophication which generally promotes excessive plant growth and decay, favouring simple algae and plankton over other more complicated plants, and causes a severe reduction in water quality.

Water that is fit for drinking is called potable water.

Increasing CO₂ in the atmosphere is responsible for global warming.

Northern, Central and Eastern regions of India are sustained by the Ganga river.

Carbon monoxide (CO) has high affinity for haemoglobin. It reduces the oxygen carrying capacity of the blood.

Oxygen is not a gas that causes global warming.

Dams are not the direct source of air pollution.

Sedimentation method is not used to make water safe for drinking. It does not kill the harmful microbes present in water.

Greenhouse gases do not cause water pollution. They cause air pollution.

Water vapours and certain gases in the atmosphere absorb infrared radiations, causing what is called the greenhouse effect. These infrared radiations come from materials on the earth's surface that have been heated by sunlight. These absorbed infrared radiations heat up the atmosphere. 

When coal and petroleum are burnt, oxides of sulphur (sulphur dioxide), oxides of carbon (carbon dioxide) and oxides of nitrogen (nitrogen dioxide) are released.

Unleaded petrol is not an alternative form of fossil fuel.

Seawater is a mixture of both salt and water. The water is solvent and the salt is solute and they are fairly balanced out.