Which of the following is a major cause of air pollution ?
Burning of fossil fuels
The burning of fossil fuels is the major cause of air pollution — option 2.
What it releases. Coal, petroleum and natural gas burnt in power stations, vehicles, factories and homes give off the whole range of the principal air pollutants :
| Pollutant | Source in combustion | Effect |
|---|---|---|
| Particulate matter, PM2.5 and PM10 | Incomplete combustion, ash | Penetrates the lungs and the bloodstream; the pollutant most closely linked to mortality |
| Sulphur dioxide | Sulphur in coal and diesel | Acid rain, respiratory illness |
| Oxides of nitrogen | Nitrogen of the air at high flame temperature | Acid rain, and photochemical smog with hydrocarbons |
| Carbon monoxide | Incomplete combustion | Binds haemoglobin in place of oxygen |
| Carbon dioxide | Complete combustion | The principal greenhouse gas |
Why the other three are wrong here. Each is a genuine environmental problem, but of a different kind :
| Option | What it chiefly causes |
|---|---|
| Disposal of plastics | Land and marine pollution; it pollutes the air only if the plastic is burnt, which is a form of combustion |
| Deforestation | Loss of habitat, soil erosion, and a reduced sink for carbon dioxide — it worsens the effect of pollution rather than emitting pollutants |
| Excessive pesticides | Soil and water pollution, and bio-magnification along food chains |
The Indian picture. Coal supplies the greater part of India’s electricity, and vehicle numbers have grown steeply, so both stationary and mobile fossil-fuel sources are large. To these are added the burning of crop stubble in the north-west, construction dust, and biomass burnt in rural kitchens. Several Indian cities appear near the top of world rankings for PM2.5, and the responses — the National Clean Air Programme, the leap from Bharat Stage IV to BS-VI fuel standards in 2020, the Ujjwala scheme for LPG connections and the push for electric vehicles — are all aimed at exactly this source.
Hence, the answer is burning of fossil fuels.
Important Questions from Environmental pollution
Photochemical smog is a resultant of the reaction among
Which of the following is NOT responsible for the degradation of our environment?
With reference to furnace oil, consider the following statements:
1. It is a product of oil refineries.
2. Some industries use it to generate power.
3. Its use causes sulphur emissions into environment.
Which of the statements given above are correct?
Why is there a concern about copper smelting plants?
1. They may release lethal quantities of carbon monoxide into environment.
2. The copper slag can cause the leaching of some heavy metals into the environment.
3. They may release sulphur dioxide as a pollutant.
Select the correct answer using the code given below.
Magnetite particles, suspected to cause neurodegenerative problems are generated as environmental pollutants from which of the following?
1. Brakes of motor vehicles
2. Engines of motor vehicles
3. Microwave ‘Stoves within homes
4. Power plants
5. Telephone lines
Select the correct answer using the code given below.
