Environment Pollution: Classification, Causes and Its Types 

Environmental Pollution
Environmental Pollution

Environmental Pollution refers to any addition of unwanted material in the environment due to human activities that lead to undesirable changes in the environment and ecology. For example, sewage water being released in clean water sources like tanks, rivers, etc. is an example of water pollution.

The different agents that cause environmental pollution are called pollutants. Pollutants can be chemicals, biological materials, or physical things that get added into the environment by accident that are directly or indirectly harmful to people and other living things.

On the Basis of Persistence Primary Pollutants
– They persist in the form in which they are added to the environment e.g. DDT, plastic.

Secondary Pollutants
– Formed by interaction among the primary pollutants e.g. Peroxyacetyl Nitrate (PAN) is formed by interaction of Nitrogen Oxides and Hydrocarbons.
On the Basis of Existence in NatureQuantitative Pollutants: 
– Occur in nature and become pollutant when concentration reaches beyond a threshold level. E.g. Carbon Dioxide, Nitrogen Oxide.

Qualitative Pollutants: 
– These are man-made and do not occur in nature. E.g. fungicides, herbicides, DDT etc.
On the Basis of Biodegradability Biodegradable Pollutants:
– Waste products or the pollutants which are decomposed/ degraded by natural processes microbial action. E.g. sewage.

Non-Biodegradable Pollutants
– The pollutants which don’t decompose naturally or decompose slowly e.g. DDT, Aluminium cans.
On the Basis of OriginNatural: 
– These pollutants are released during natural processes, such as volcanic eruptions, forest fires, grass fires, etc.

– These pollutants are released during anthropogenic activities, such as CO2 emission from the burning of fossil fuels.
  • Pollution affects the very factors which support life on the ear, such as the air we breathe, the water we drink and, at large, the ecosystems we depend upon. Thus, it poses a threat to life on the earth. 
  • Pollution poses one of the greatest challenges to the health of humans and other living beings.
  • Though it affects the overall well-being of the entire society, vulnerable sections like the poor, the children, the women etc are affected disproportionately by it. 
  • Pollution has its negative impacts on the economy as well. For example, as per a study, water pollution would cause a loss of around 6% of India’s GDP by 2050 due to loss in sectors like fishing, agriculture, water intensive industries etc. 
  • Other socio-economic impacts of pollution include food insecurity due to decreased agricultural yield, forced migration due to water crisis etc. 
  • Rapid increase in human population has increased anthropogenic activities by manifold. Most of these activities, in some way or the other, add some unwanted things to the environment. 
  • Rapid urbanization in recent times has led to increased construction activities. This, in turn, is causing environmental pollution through different ways, such as release of dust in air, generation of waste materials etc. 
  • Increased population and urbanization have meant increased transportation activities. This, in itself, is a major source of pollution. 
  • An increased focus on industrialization of late is leading to rapid generation of industrial wastes and emissions, and hence environmental pollution. 
  • Some agricultural activities also lead to environmental pollution. For example, excessive use of fertilizers and pesticides not only pollutes the soil but also nearby water bodies due to spill over. 
  • There are many other causes of environmental pollution, such as Burning of fossil fuels, increased use of chemicals, etc.

Depending on the source as well as destination of the pollutants, there are various types of pollution. Some major of them can be seen as follows:

  • As per WHO, Air Pollution is contamination of the indoor or outdoor environment by any chemical, physical or biological agent that modifies the natural characteristics of the atmosphere.
  • According to WHO data, 99 percent of the world’s population breathes air that contains high levels of pollutants and exceeds WHO guideline limits, with low and middle-income countries experiencing the highest exposures.

Causes of Air Pollution

  • Industrial emissions, household emissions , motor vehicles emissions,  forest fires etc are some common sources of air pollution.
  • Pollutants of major public health concern include Particulate Matter, Carbon Monoxide, Ozone, Nitrogen Dioxide, and Sulphur Dioxide.

Measures Taken to Control Air Pollution

  • The Air (Prevention & Control of Pollution) Act 1981
  • National Clean Air Programme (NCAP)
  • Continuous Ambient Air Quality Monitoring System (CAAQMS)
  • Green Crackers developed by CSIR-NEERI
  • The Great Green Wall of Aravalli 
  • Some states like Delhi has built Smog Towers to tackle air pollution.

Water pollution refers to release of unwanted substances into subsurface groundwater or into water bodies like lakes, streams, rivers, estuaries, and oceans to a level which negatively impacts the beneficial use of the water or natural functioning of ecosystems.

When harmful chemicals or microorganisms contaminate a stream, river, lake, ocean, aquifer, or other body of water, the water’s quality deteriorates and it becomes toxic for both humans and the environment.

  • Dissolved oxygen (DO) levels drop, Biological Oxygen Demand (BOD) rises, aquatic species perish, eutrophication occurs, etc. as a result of water pollution.

Causes of Water Pollution

  • Agriculture is one of the primary sources of water pollution. Animal waste from farms and livestock operations, pesticides, and fertilizers wash nutrients and pathogens like bacteria and viruses into our waterways.
  • More than 80 percent of the world’s wastewater flows back into the environment without being treated or reused, according to the United Nations.
  • Nearly half of the estimated 1 million tons of oil spills over into marine environments.
  • Radioactive substances generated by uranium mining, nuclear power plants and the hospitals that use radioactive materials for research and medicine. These waste can persist in the environment for thousands of years, making disposal a major challenge.

Measures Taken to Control Water Pollution

International Measures to Tackle Water Pollution
  • International Conventions to Mitigate Marine Pollution 
  • Convention on Dumping Wastes at Sea or London Convention (1972)
  • The 1972 Convention on the Prevention of Marine Pollution by the Dumping of Wastes and Other Matter, also known as “LC ’72” or the “London Convention,”
  • United Nations Convention on Law of the Sea (UNCLoS).
Measures Taken in India to Tackle Water Pollution
  • Water (Prevention and Control of Pollution) Act, 1974:
  • Initiatives to rejuvenate rivers, like Ganga Action Plan, Yamuna Action Plan etc. 
  • Initiatives taken by the Central Pollution Control Board to tackle contamination and over-exploitation of groundwater.
  • Noise Pollution is defined by the World Health Organization (WHO) as noise that is louder than 65 decibels (dB). 
  • Precisely speaking, noise becomes harmful above 75 dB and painful above 120 dB Thus, it is advised to keep noise level below 65 dB during the day. 
  • An ambient noise level advisable for the nighttime is 30 dBas restful sleep cannot be achieved with noise levels above this. 
  • The current status of noise pollution all over the world can be seen through the United Nations Environment Programme’s report titled ‘Frontiers 2022: Noise, Blazes and Mismatches’ which enlist the noisiest cities in the world.
S.No.CityCountryNoise Pollution
5Ho Chi Minh CityVietnam103dB

Suggested Measures to Control Noise Pollution

  • Suppression of noise at the source
  • Acoustic zoning
  • Sound insulation at construction sites
  • Planting trees
  • Strict legislative measures.
  • The contamination of soil with abnormally high concentrations of toxic substances is referred to as soil pollution.
  • Given the numerous health risks it contains, it is a serious environmental concern. For instance, exposure to soil with high Benzene concentrations increases the risk of developing Leukaemia.

Causes of Soil Pollution

  • Phenomena such as loss of organic carbon, erosion, increased salt content, acidification, compacting, and chemical pollution are the major causes of current soil degradation.

Suggested Measures to Tackle Soil Pollution

  • Promote eco-friendly practices in business, agriculture, and stock breeding and other sectors of the economy.
  • Ensure an efficient transportation and treatment of wastewater through proper urban planning. 
  • Increase topsoil conservation, landscape restoration,
  • Mining waste management.
  • When radioactive elements are accidentally present in the environment or atmosphere and pose a risk to the ecosystem owing to radioactive decay, this is known as radioactive pollution.
  • The radioactive materials create damage by releasing potentially harmful ionizing radiation into the environment, such as Alpha or Beta particles, gamma rays, or neutrons.

Causes of Radioactive Pollution

  • Nuclear Accidents from Nuclear Energy Generation Plants
  • Use of Nuclear Weapons as Weapons of Mass Destruction (WMD)
  • Use of Radioisotopes in Health and other sectors.
  • Mining 
  • Spillage of Radioactive Chemicals
  • Cosmic Rays and Other Natural Sources
  • Nuclear Waste Handling and Disposal
  • Light pollution is the presence of inappropriate, unwanted and excessive artificial lighting.
  • Too much light pollution has negative impacts on the environment and human health, obstructs astronomical research, disturbs ecosystems, and wastes energy.
  • Specific categories of light pollution include light clutter, light trespass, over-illumination, glare and sky glow
  • To overcome these challenges, use of Led lights, reduce the use of decorative lighting, minimise the use of light etc.
  • Nitrogen pollution results from an overabundance of nitrogen compounds, such as ammonia and nitrous oxide. Sometimes, the usage of synthetic fertilizers causes this pollution. 
  • Another possible cause is the breakdown of large quantities of animal manures and slurry, which are frequently present in intensive livestock units.
  • It may have detrimental effects on our climate, the ecosystem, and  health.

Suggested Measures to Tackle Nitrogen Pollution

  • Use climate and nature-friendly growing methods and avoid using synthetic fertilisers.
  • Support organic and agro-ecological farmers in order to promote farmers to transition to a future with less nitrogen.

Thus, various types of pollutions being caused by different anthropogenic activities have the potential to cause damage to the existence of life on the earth. India and the world must adopt a “green vision” as part of the development agenda. The time has come to add “clean environment” to the list of basic necessities – “roti-kapada-makaan”. 


  • Nrdc
  • WHO
  • National Geography


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