Air Pollution - Sources & Effects on Environment | UPSC CSE

Air Pollution is one of the most important topics for the UPSC Civil Services Exam. The questions from this topic are asked both in Prelims and Mains. In this article, we’ll discuss some important concepts and provide you with short notes for revision on air pollution for the UPSC exam.

What Is Pollution?

Pollution is defined as the addition or exessive addition of certain materials to the physical environment thereby making it less fit or unfit for living. These materials are called pollutants, and can be classified into various categories:

On the basis of

Type of Pollutant


Form in which they exist

Primary Pollutant

That is emitted directly from the source. Example: Oxides of Sulphur and Nitrogen

Secondary Pollutant

That is formed when pollutants combine with each other. Example: Ground Ozone, Acid Rain

Nature of disposal

Biodegradable Pollutants

These pollutants can be degraded by microbial action. Example: Sewage

Non-Biodegradable Pollutants

These pollutants cannot be degraded and remain a part of the environment for a long period of time. Example: Plastic, Glass

Natural Vs Artificial

Natural Pollutants

They are already present in nature but become pollutants upon crossing a threshold concentration. Example: Carbon Dioxide

Artificial Pollutants

These are artificially made by humans. Example: Herbicides, Pesticides, DDT

Physical Form of Existence

Particulate Pollutants

Example: Lead, Fly Ash

Metallic Oxides, Nanoparticles

Gaseous Pollutants

Carbon monoxide (CO)

Carbon dioxide (CO2)

Chlorofluorocarbons (CFCs)

Ozone (O3)

Nitrogen oxide (NOx)

Sulfur dioxide (SO2)

Major Air Pollutants | Environment for UPSC CSE

Major air




Sulphur Dioxide (SO2)

  • Coal-based thermal power plants

  • Paper, Metal smelting industries

  • Contributor to Smog and Acid Rain

  • Eye and throat irritation

  • Cough and allergies

  • Impairs enzyme function in the respiratory system

  • Reduces the exchange of gases from the lung surface.

NOx (Oxides of Nitrogen)

  • Thermal power plants

  • Industries

  • Vehicles

  • Irritation and inflammation of lungs

  • Breathlessness


  • Petrol-diesel

  • Lead Batteries

  • Paint

  • Hair Dyes

  • Carcinogenic Properties (Cancer-causing)

  • Causes several life-threatening Nervous and digestive problems

  • Kidney Ailments

  • Impaired child growth and brain damage

CO (Carbon Mono-oxide)

  • Incomplete burning of carbon-based fuels

  • Combustion of natural and synthetic products

  • Lowers the amount of oxygen entering our blood

  • Slows down natural reflexes

  • Headache and unconsciousness, in severe cases, can cause death. 

CO2 (Carbon Dioxide)

  • Burning of fossil fuels

  • Greenhouse Gas (Causes global warming)

  • Impairs reflexes

  • Causes carbonic rains in areas with higher concentrations of CO2.

Tropospheric Ozone

  • Vehicular and Industrial Emission

  • Itchy Eyes

  • Chronic Bronchitis

  • Pneumonia

Suspended Particulate Matter (Smoke, Dust, and Vapor)

  • Vehicular and Industrial Emission

  • Burning of Fossil Fuels

  • Lung Damage and Respiratory Diseases

  • Reduced development of Red Blood Cells.

  • Pulmonary Malfunctioning

  • Haze Formation


  • Found in petrochemicals and used as a fuel additive

  • Increases cancer risk and a major cause of bone marrow failure.


  • Used in plastic and chemical industries in the production of Polyethylene and other polymers.

  • Excess exposure can cause headaches and dizziness.

  • Ethylene oxide is a carcinogen.


  • Occurs naturally as a fibrous mineral.

  • Asbestos mining and sheet manufacturing

  • Prolonged exposure and inhalation can be very harmful.

  • Can cause asbestosis and respiratory problems.


  • Industrial emissions and waste

  • Can cause life-altering diseases like Minamata, Gingivitis, Tremor, Insomnia, Nervous disorder, and memory loss.

Radioactive Pollutants

  • Includes Radon, Radium, Cosmic Rays, Beta Rays, X-Rays

  • Leukemia (Blood Cancer)

  • Permanent Genetic Changes

  • Affects cell membrane and cell enzymes

Biological Pollutants

  • Includes Pollen, Mites, Fungi, Bacteria, and parasites

  • Allergies and diseases such as Asthma and Hay Fever

Measuring Air Pollution | Government Interventions For Air Pollution

Name of the Programme

National Air Quality Monitoring Programme

National Air Quality Index

SAFAR (System of Air Quality and Weather Forecasting and Research)

Launched In

1982 (Revised in 1994 and 2009)



Executed By

Central Pollution Control Board

Central Pollution Control Board

Introduced by the Ministry of Earth Sciences, SAFAR is developed by the Indian Institute of Tropical Meteorology (IITM), Pune, and is operationalized by the India Meteorological Department (IMD).


It determines the status and trends of air quality in 312 cities and towns. It is calculated for 12 pollutants namely PM10, PM2.5, NO2, SO2, CO, Ozone, Ammonia, Lead, Arsenic, Nickel, Benzene, and Benzopryne.

AQI(Air Quality Index) is an index for reporting daily air quality. It focuses on the health effects one might experience within a few hours or days after breathing polluted air. AQI is calculated for eight major air pollutants:

Ground-level ozone, PM10, PM2.5, Carbon monoxide, Sulfur dioxide, Nitrogen dioxide, Ammonia, Lead.

to measure the air quality of a metropolitan city, by measuring the overall pollution level and the location-specific air quality of the city.

SAFAR is an integral part of India’s first Air Quality Early Warning System operational in Delhi

This is the brief overview of Air Pollution for the UPSC Civil Services Examination. This topic is extensively discussed in our General Studies course for the UPSC Mains exam.

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