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  • Pollution is the deterioration of the environment due to the addition of harmful materials (pollutants) to it.
  • Pollutants can be natural ex- volcanic ash OR Anthropogenic such as CO2 emission from the burning of fossil fuels.
  • They can also be biodegradable or non-biodegradable based on their disposal and Primary or secondary based on their formation.
  • Types of Pollution: Air Pollution, Water Pollution, Radioactive pollution, Soil & Plastic pollution, etc.


  • Air pollution is the degradation of air quality due to the contamination of pollutants.
  • It was the 4th leading risk factor for early death worldwide in 2019 (State of Global Air Report 2020).
  • Industries (51%), Vehicles (27%), and Crop burning (17%) are the largest contributor to Air pollution.




Types of air pollutants:

Primary pollutants – Enter the atmosphere directly from their source. E.g. – CO2.
Secondary pollutants -Forms from a chemical reaction of primary pollutants. Ex: Ozone (O3), Acid rain.
Indoor air pollution (IAP) – The poor air quality within and around buildings is called IAP. It is caused by burning solid fuel such as firewood, dung for cooking.
Outdoor (ambient) air pollution – originates from natural and anthropogenic sources. EX – bushfires, volcanoes, Automobile emission, etc.




  • Fog is a cloud of smoke particles, water droplets, or mixtures of these components suspended in the air.
  • Fog usually appears over a region of high pressure where humidity is greater than 75%.
  • It reduces visibility & causes accidents.



  • Smoke + Fog = Smog – is a type of intense air pollution.
  • Smog is a harmful mixture of fog, dust & air pollutants such as nitrogen oxides, VOCs, etc.
  • Impacts: cause itchy, burning eyes, damage lung tissues, cardiac and respiratory disorders, it can kill plants etc.
  • Types: Sulfurous smog & Photochemical smog
SULFUROUS SMOG (London smog)
  • This occurs in a cool humid climate.
  • It is a mixture of Smoke, Fog & Sulphur Dioxide.
  • Chemically, it is a reducing mixture and so it is also called reducing smog.
  • It is also called winter smog or classic smog.



  • Produced when sunlight reacts with Nitrogen Oxides & volatile organic compounds in the atmosphere which results in the formation of Bad ozone.
  • It is visible as a brown haze.
  • Contains more oxidizing agents.
  • Often referred to as “summer smog” or “Los Angeles smog,” it occurs most prominently in urban areas.


  • It is a component of fine particulate matter formed through the incomplete combustion of fossil fuels, biofuel, and biomass.
  • It is a short-lived pollutant with a lifetime of only days to weeks.
  • It is one of the main types of particles in soot.
  • PM is a mixture of solid particles & liquid droplets found in the air.
  • PM10: are inhalable particles sized 10 micrometers or less in diameter.
  • PM2.5: fine inhalable particles, sized 2.5 micrometers or less in diameter. These are more harmful to health as they move freely with air current & block the tiny pores in our lungs.


  • Normal rain has a pH of about 5.6 when pH falls below this; it is called Acid rain (pH 4.2 to 4.4).
  • Acid rain results when Sulfur Dioxide (SO2) & Nitrogen Oxides (NOX) react with water, oxygen & other chemicals to form Sulfuric & Nitric acids.
  • NOx + SO2 + Moisture + other chemicals à Acid Rain (HNO3 + H2SO4)
  • Effects: Harms microorganisms in the soil + inhibit the activity of nitrogen fixation bacteria + soil acidification + ocean acidification + affects the growth of plants + food chain + kill aquatic animals + corrosion of metals & weathering of stone buildings & statues.


Common Air Pollutants and Their Effects


Pollutant Sources Effects
Particulate matter (PM) Vehicles, power plants, construction activities, oil refinery,

railway yard, industries, etc.

Cardiovascular diseases, reduces visibility (haze)
Nitrogen dioxide (NO2) Emissions from combustion processes Can aggravate respiratory diseases, acid rain, Hazy weather
Sulfur dioxide (SO2) Burning of fossil fuels, power plants, metals processing and smelting facilities, vehicles Affects respiratory system & functions of the lungs. causes irritation of the eyes, chronic bronchitis, Acid rain
Ozone (O3) Results from photochemical reactions b/w NOx & VOCs in presence of sunlight. Affect the lungs, the respiratory tract, and the eyes, lung cancer


  • Fly ash is a fine powder that is a byproduct of burning pulverized coalin electric power generating plants.
  • Indian coal is of low grade with more ash content (30-45 %) compared to imported coal.
  • MAIN COMPOSITION OF FLY ASH: Silicon dioxide (SiO2), Aluminum oxide (Al2O3) & Calcium oxide (CaO).
  • MINOR CONSTITUENTS: Arsenic, Beryllium, Boron, Cadmium, Chromium, Hexavalent Chromium, Cobalt, Lead, Manganese, Mercury, Molybdenum, Selenium, Strontium, Thallium, Vanadium, & Un-burnt Carbon.
  • NEGATIVE EFFECTS OF FLY ASH: It contains acidic, toxic, & radioactive matter + Carcinogenic & damages nervous system + causing cognitive defects, developmental delays, and other respiratory diseases.




Utilization of Fly Ash:

  • As a replacement for some of the Portland cement contents.
  • GoI has made it mandatory for use of fly ash bricks in construction activities happening 500 km around thermal power plants.
  • As soil conditioner for acidic soils. Also, it improves the porosity & water holding capacity of the soil.
  • Maharashtra is the first state in India to adopt the Fly Ash Utilization Policy.
  • The Govt has launched the ‘ASHTRACK’ mobile app for fly ash utilization.


THE AIR (Prevention & Control of Pollution) ACT 1981
  • It was enacted to prevent, control& abate air pollution.
  • Under this Act, all industries operating within designated air pollution control areas must obtain a permit from the State Boards.
  • The states are required to prescribe emission standards for industry & automobiles.
  • It expanded the authority of the CPCB to include Air Pollution under it.
  • The 1987 amendment introduced a citizen’s suit provision into the Air Act & extended the Act to include Noise pollution.




BS Norms

  • These are emission standards to reduce vehicular pollution.
  • Norms set by CPCB (Central Pollution Control Board) under the Ministry of Environment & Forests and climate change.
  • India introduced emission norms in 1991 & BS-1 in 2000 based on European standards.
  • India skipped BS-V & moved to BS-VI norms directly in 2020.
  • BS-VI fuel is estimated to bring around 80% reductions in Sulphur content.
  • BS-VI will cut down the harmful NOx (nitrogen oxides) from diesel cars by nearly 70% and 25% in the petrol cars.
  • BS-VI will bring down the cancer-causing Particulate Matter in diesel cars by a phenomenal 80%.


  • CPCB launched AQI in 2014 under the Swachh Bharat Abhiyan to disseminate information on air quality in an easily understandable form for the general public.
  • It transforms complex air quality data of 8 pollutants into a single number, nomenclature, and color.
  • AQI has six categories of air quality:
  • Eight pollutants : Particulate Matter (PM10), Particulate Matter (PM2.5), Nitrogen Dioxide (NO2), Sulphur Dioxide (SO2), Carbon Monoxide (CO), Ozone (O3), Ammonia (NH3), and Lead (Pb).


  • Notified by CPCB (under powers given to it by Air Act, 1981) in 2009.
  • It covers 12 pollutants: Sulphur Dioxide, Nitrogen Dioxide, PM10, PM5, Ozone, Lead, Carbon Monoxide, Ammonia, Benzene, Benzo Pyrene, Arsenic, Nickel.


  • An initiative of the Ministry of Earth Sciences and Environment (MoES).
  • Objective: To predict extreme air pollution events over the Delhi region & give alerts to take necessary steps as per the Graded Response Action Plan (GRAP).
  • It uses data of stubble burning incidents from the past 15 years to predict and help authorities to act in advance.
  • It is developed by the Indian Institute of Tropical Meteorology, Pune.


  • It is a set of stratified actions to enforce in the NCR if the pollution level reaches a certain specified limit.
  • It was formulated by Environment Pollution (Prevention & Control) Authority (EPCA) on the advice of the Supreme Court in 2016.
  • Objective: To specify actions required to control air pollution, when the air quality moves from ‘Poor’ to ‘Very Poor’ on AQI.
  • GRAP works only as an emergency measure, not throughout the year.
  • These measures were earlier implemented in Delhi only. However recently GRAP has been extended to the NCR towns also.


  • The CPCB is a statutory organization established under the Water (Prevention and Control of Pollution) Act, 1974.
  • It is also entrusted with the powers & functions under the Air (prevention and control of pollution) Act,
  • It works under the Ministry of Environment, Forest & Climate Change (MoEF&CC).
  • Important functions: To prevent, control & abate water & air pollution in the country + To provide technical services to the MoEF&CC under the provisions of the Environment (Protection) Act, 1986 + Collect, compile & publish technical and statistical data relating to water and air pollution.


  • These are produced using less harmful raw materials & have additives which reduce emissions by suppressing dust.
  • Developed by CSIR-NEERI
  • Names of these crackers are: “Safe Water Releaser (SWAS)”, “Safe Minimal Aluminum (SAFAL)” & “SAFE THERMITE CRACKER (STAR)”.
  • Firecrackers are regulated by PESO.
  • PESO (Petroleum & Explosives Safety Organisation) is an office under the Department for Promotion of Industry & Internal Trade, Ministry of Commerce and Industries.


  • EPCA is Supreme Court mandated statutory body.
  • Notified by Environment Ministry in 1998 under Environment Protection Act, 1986.
  • Objective: to protect and improve the environmental quality & pollution control in the NCR-National Capital Region (Delhi).
  • Enforces Graded Response Action Plan (GRAP) in NCR as per the pollution levels.
  • EPCA has the power to take actionsuo-moto.


  • Air quality in Delhi is the worst of any major city in the world – WHO




Causes of air pollution:

  • It is a yearly problem and seasonal.
  • Geography: change in wind direction during winter (northwesterly), dip in wind speed, & dust storms (from the Gulf) make the landlocked Delhi region more prone to pollution.
  • Vehicular Pollution& firecrackers
  • Emissions from nearby industries & thermal power plants.
  • Stubble burning in surrounding states.



Measures taken to tackle:


  • The introduction of BS-VI vehicles, push for electric vehicles (EVs), Odd-Even scheme to reduce vehicular pollution.
  • Delhi is the 1st city in India running with BS-VI fuels & scheduled to use Hydrogen-CNG
  • Implementation of the GRAP
  • Subsidy to farmers for buying Turbo Happy Seeder to reduce stubble burning.
  • Torrefaction.
  • Development of the National AQI for public information.
  • The initiative of ‘The Great Green Wall of Aravalli’ green ecological corridor along with Aravalli range from Gujarat to Delhi.




Hydrogen- Compressed Natural Gas (HCNG)

HCNG is a hydrogen-enriched Compressed Natural Gas (CNG).



  • Cleaner, safer & more economical than CNG
  • It reduces the engine’s unburned hydrocarbon emissions and speeds up the process of combustion.
  • Ensures 70% more Carbon Monoxide reductions compared to CNG.


  • It requires new infrastructure to prepare HCNG
  • Determining the most optimized H2/ NG (Natural Gas) ratio
  • Costlier than CNG


TORREFACTION: is a thermal process to convert biomass into a coal-like material, which has better fuel characteristics than the original biomass. Torrefied biomass is more brittle, making grinding easier & less energy-intensive.


HAPPY SEEDER: is a tractor-mounted machine that cuts & lifts rice straw, sows wheat into the bare soil, and deposits the straw over the sown area as mulch.


  • It will be a 1,400km long & 5km wide green belt from Gujarat to the Delhi-Haryana border.
  • The ‘Green wall’ idea mooted in the COP14 of UNCCD, India in 2019.
  • It intends to restrict land degradation & the eastward march of the Thar Desert.
  • Also, it will act as a barrier for dust coming from the deserts in western India and Pakistan.


  • It was launched by the MoEF&CC in 2019
  • It is the first-ever effort by India to frame a national framework for air quality management with a time-bound reduction
  • Objective: to reduce particulate matter (PM) pollution by 20-30% in at least 102 non-attainment cities by2024 with 2017 as the base year.
  • Non-attainment cities: These are those that have fallen short of the NAAQS for over five years.


  • Nitrogen becomes a pollutant when it escapes into the environment & reacts with other organic compounds.
  • Sources: Agriculture, fossil fuel burning sewage etc.,
  • Impacts: global warming, acid rain and eutrophication etc.,
  • UNEP’s Colombo Declaration: Aims to halve Nitrogen waste by 2030
  • Joint initiative of UNEP, the International Nitrogen Initiative & Global Environmental Facility




  • Bhopal gas tragedy, 1984
  • Caused by Methyl Iso Cyanide (MIC) gas leak from the Union Carbide Factory, Bhopal.
  • MIC is used in the manufacture of polyurethane foam, pesticides, & plastics.
  • Visakhapatnam Gas leak, 2020
  • Caused by Styrene gas leak at the LG Polymers chemical plant, Vizag.
  • Styrene (C6H5CH=CH2)is a flammable liquid (can evaporates easily) used in the manufacturing of polystyrene plastics, fiberglass, rubber, & latex.
  • Exposure to Styrene can cause Irritation to the eyes, skin, nose & damages Central nervous system and kidney.
  • The Chernobyl disaster, 1986, Ukraine (the then USSR).
  • Fukushima Daiichi nuclear disaster in Japan, 2011.


  • Water pollution is the contamination of water bodies, usually as a result of human activities.
  • Point pollution sources, where the source is a well-defined location.
  • Non-point pollution sources, which are spread over larger areas.
  • Causes: Agricultural sources, Sewage water, Industrial effluents, Thermal Pollution, Oil-spills, ships & other economic activities.
  • Effects: Decline on Dissolved oxygen, Increase in BOD, Death of Aquatic species, Eutrophication etc.


  • DO is the amount of oxygen that is present in water.
  • Oxygen is poorly soluble in water. Its solubility is related to Pressure & Temperature.
  • The higher the temperature, the lower is the DO levels in the water.
  • During summer due to increased biological oxidation, the DO level reduces.
  • BOD is the amount of oxygen required by microorganisms for the aerobic decomposition of organic matter in the water body.
  • It is a measure of the amount of oxygen required to remove waste organic matter from water.
  • It is used as an indicator of the degree of pollution.
  • The greater BOD indicates the lower amount of DO available in the water.
  • COD measures the amount of oxygen in ppm required to oxidize organic and oxidizable inorganic compounds in the water sample.
  • Breakdown of organic matter is done by chemical reagents.
  • CoD is a slightly better mode used to measure pollution load in the water than BoD.



  • It indicates excessive plant and algal growth due to the increased availability of nutrients (Nitrates & Phosphates) in water bodies.
  • It occurs naturally but human activities such as fertilizers, industrial wastewater, sewage disposal accelerate it.






  • Algal blooms limit light penetration, reducing growth and causing the death of plants and marine species.
  • Dead Zones (Biological Deserts): When algal blooms die, microbial decomposition severely depletes dissolved oxygen & creates a hypoxic or ‘dead zone. Most of the animal life either dies or migrates from the zone.
  • Water pollution
  • Affects biodiversity & productivity of the ecosystem.
  • New species invasion & loss of native species.


Tubifex worms or sludge worm: These pose a significant risk for trophic transfer & Bio-magnification of micro-plastics up the aquatic food chain. They can survive in heavily polluted areas where almost no other species can endure. It is an indicator species for polluted water.


  • It is the process where toxic substances move up the food chain and become more concentrated at each level. Ex: DDT
  • It adversely affects human and marine life. It can also destroy Coral Reefs.
  • It can disrupt the food chain.


  • Ocean acidification is the reduction in the pH of seawater due to excessive absorption of CO2 by the oceans.
  • Effects: Loss of Coral reefs, marine biodiversity, disruption in food chain etc.




Disease Potential sources / cause& their effects
Minamata Neurological disease caused by severe mercury poisoning.
Blue Baby Syndrome

It is a bluish discoloration of infants’ skin because of poorly oxygenated blood due to Nitrate contamination in water.
Itai-Itai Cadmium pollution causing lung and liver cancer.
Skeletal Fluorosis Fluoride contamination causing teeth deformity, hardening of bones and joint pains.
Trachoma An infectious eye disease caused by unclean water


  • Thermal pollution is the degradation of water quality by any process that changes ambient water temperature.
  • CAUSES / SOURCES OF THERMAL POLLUTION: Industries & Nuclear power plants + Deforestation + Soil erosion + Urban runoff + Natural causes like volcanoes + Hot springs + Bio-medical wastes + Domestic sewage
  • EFFECTS NEGATIVE EFFECTS ON HUMAN, WILDLIFE & MARINE LIFE: Increase in toxin levels in water + Decrease in DO (Dissolved Oxygen) Levels + Disrupts the stability of the food chain + Affects reproductive process + Species migration & Loss of biodiversity.
  • CONTROL MEASURES: Could be reused for Biological applications such as soil warming, Fish culture etc.



Soil pollution is the deterioration in quality & fertility of soil due to the presence of toxic pollutants.


CAUSES: Natural + Anthropogenic EFFECTS
  • Poor Agricultural & Livestock practices.
  • Improver solid waste management
  • Unsafe storage of hazardous chemicals & nuclear waste
  • Urban and transport infrastructure
  • Natural calamities
  • Naturally contributes to air pollution
  • may alter plant metabolism & reduce crop yields
  • Bio-magnification
  • leads to soil erosion & eutrophication
  • Reduced nitrogen fixation & loss of soil nutrients
  • Carcinogenic


Soil Contaminants and Their Effects On Health & Environment


Lead (Pb)
  • Lead paint, mining, foundry activities, vehicle exhaust, construction-activities, agriculture activities, and batteries etc.,
  • May leads to Learning difficulties, abdominal cramps & vomiting, Fatigue, Neurological problems, Headache, Growth reduction etc.
Mercury (Hg)
  • From mining, incineration of coal, alkali and metal processing, medical waste, volcanoes & geologic deposits.
  • A tingling sensation in one’s limbs, Speech impairment, Loss of balance & coordination, Tremors, Depression, mood changes, Severe neurological damage, Itching, burning, pain, Damage to brain, kidneys, and lungs, Pink disease (acrodynia) – a skin discoloration, High BP & Hyper-salivation
Arsenic (As)
  • From mining, coal-fired power plants, lumber facilities, electronics industry, foundry activities, agriculture, natural accumulation.
  • Leads to Neurotoxicity, abdominal pain, muscle cramps, blood in urine, pregnancy complications, infant mortality, cognitive problems in infants, bladder or lung cancer
Herbicides /Insecticide
  • From agricultural activities, gardening etc.
  • Birth defects, Endocrine disruption, Reproductive problems, Leukemia and other cancers.
  • Mining; foundry activities; construction activities
  • Lung cancer, Neurological problems, Childhood developmental issues, Kidney and liver failure, Cardiovascular disease.



It is an unwanted or excessive sound that can have adverse effects on human health, wildlife, and the environment.



Effects of Noise Pollution

  • Affects both the health & behavior, of people and wildlife.
  • Cardiovascular disorders, hypertension, high-stress levels, tinnitus, hearing loss, sleep disturbance
  • Cognitive Issues & Behavioral Change


Control measures

  • Control at receiver’s end
  • Suppression of Noise at Source
  • Acoustic Zoning
  • Sound Insulation at Construction Stages
  • Planting trees
  • Strict legislative measures


  • Radioactive pollution is the result of the release of radioactive substances into the environment.
  • Radioactive substances are those which can emit high energy particles like alpha, beta & gamma rays.
  • These substances are highly unstable & are continuously emitting these particles to gain some stability.
  • It is not a constant or regular phenomenon & hence the duration and frequency of pollution vary with time & conditions.



Causes / Sources of Radioactive Pollution

  • Uranium mining& processing
  • Nuclear power reactors, & use of radionuclides in industries
  • Nuclear tests carried out by the defence personnel, wars; and
  • Disposal of nuclear waste.
  • Natural sources like; radiation from space & earth crust.


  • Genetic Mutations
  • Causes cancer, leukemia, anemia, hemorrhage, premature aging etc.,
  • Soil infertility
  • Radioactive material can enter the food chain, remains in the environment for hundreds of years causing somatic damage ie damage to organs of the body.


  • Light pollution is excessive, misdirected, or obtrusive artificial (usually outdoor) light.
  • Consequences: it washes out starlight in the night sky, interferes with astronomical research, disrupts ecosystems, has adverse health effects and wastes energy.


  • Solid waste consists of Municipal Solid Waste (MSW), e-waste & Biomedical wastes.
  • Solid Waste Management involves a collective activity involving segregation, collection, transportation, re-processing, recycling & disposal of various types of wastes.


  • E-waste is any electrical or electronic equipment that’s been discarded.
  • India’s first e-waste clinic – at Bhopal.


E-waste sources Constituents Health effects
PCBs, glass panels, and Computer monitors Lead Damage nervous systems, & kidney

Impair child’s brain development

Resistors & Semiconductors Cadmium Accumulates in kidney&liver

Causes neural damage

Relays and switches, &PCBs Mercury Damages brain

Respiratory & skin disorders

Galvanized steel plates & decorator or hardener Chromium Causes Bronchitis
Cabling, Computer& housing Plastics &PVC Burning produces Dioxin that causes reproductive& developmental problems
Electronic equipments & circuit boards Brominated flame-retardants Disrupt endocrine systems
Front panels of CRTs Barium, Phosphorus & Heavy metals Muscle weakness & damages heart, liver
Copper wires, PCB tracks. Copper Stomach cramps, nausea, liver damage
NickelCadmium batteries Nickel Skin Allergy


Lithium-ion battery Lithium Li can pass into breast milk& may harm a nursing baby

may cause lung edema

Motherboards Beryllium Carcinogenic



E-Waste (Management) Rules, 2016
  • Notified by the Ministry of Environment, Forest & Climate Change
  • The new e-waste rules included CFL & other Mercury-containing lamps, as well as other such equipment.
  • For the first time, the rules brought the producers under Extended Producer Responsibility (EPR), along with targets.
  • Producers can have a separate Producer Responsibility Organisation (PRO) & ensure the collection & disposal of E-waste in an environmentally sound manner.
  • Deposit Refund Scheme has been introduced, wherein the producer charges an additional amount as a deposit at the time of sale and returns it to the consumer along with interest when equipment is returned.
  • The role of State Governments has been also introduced to ensure the safety, health & skill development of the workers involved in dismantling & recycling operations.
  • Bulk consumers have to file annual returns it prescribes a waste collection target of 30% waste generated for the first 2 years and progressively going up to 70% in the 7th year from rule notified.
  • Provision of penalty for violation of rules.
  • Urban Local Bodies has been assigned the duty to collect & channelize the orphan products to authorized dismantlers or recyclers.


  • It is the harmful accumulation of synthetic plastic products in the environment.
  • India aims to eliminate single-use plastic by 2022.
  • UNEP’s 2018-World Environment Day’s theme: ‘Beat Plastic Pollution’.
  • Causes / Sources of Plastic Pollution: Households + Industrial use + Bio-medical wastes + Agriculture + Fishing and marine economic activities.
  • Effects: Upsets the food chain + Contributes to Air, Soil as well as Water pollution.

  • Microplastics are any type of plastic fragment that is less than 5 mm in length. Ex: Microbeads, microfibers.
  • They enter natural ecosystems from a variety of sources, including cosmetics, clothing, & industrial processes.
  • Concerns: toxins, can block the gastrointestinal tracts of organisms.


  • The Initiative is led by UNEP & the World Tourism Organization, in collaboration with the Ellen MacArthur Foundation.
  • Aims to address the root causes of plastic pollution.
  • Developed within the framework of the ‘One Planet Sustainable Tourism Programme’.
  • It enables businesses, governments, & other tourism stakeholders to make a set of concrete & actionable commitments by 2025.


  • Ozone can be good or bad, depending on where it is found. It is a secondary pollutant.
  • Stratospheric ozone is good ozone that protects the earth from UV radiation.
  • Ground-level ozone, which is bad ozone, is a colourless & highly irritating gas that forms just above the earth’s surface (lower troposphere).




Harmful effects:

  • Health problems including chest pain, coughing, throat irritation, reduced lung function, can worsen bronchitis, emphysema, & asthma
  • It inhibits photosynthesis thus, slows down plant growth & reduces CO2 absorbing ability.
  • Decreased photosynthesis increases CO2 concentration in the atmosphere.


  • Aims to Abate Acidification, Eutrophication & Ground-level Ozone.
  • Also known as the Multi-effect protocol, was adopted by the countries of UNECE (United Nations Economic Commission for Europe).
  • The protocol sets national emission ceilings for 2010 up to 2020 for four pollutants: Sulphur dioxide, Nitrogen oxides (Nox), volatile organic compounds (VOCs) & Ammonia (NH3).
  • The protocol also is a part of the convention on long Range Transboundary Air Pollution.



Bioremediation is the process of using organisms to neutralize or remove contamination from waste.







In-situ Bioremediation

Here contaminated waste is treated right at its point of origin.

In-situ bioremediation techniques:

  • Biosparging: air & nutrients (if needed) are injected into the saturated zone to increase the biological activity of the indigenous microorganisms.
  • Phytoremediation: use of plants to remove contaminants.
  • Bioventing: blowing air through the soil to increase the oxygen level in the waste to neutralize certain oxygen-sensitive metals or chemicals.
  • Bioleaching: removing metals from soil using living organisms. For example, fish bones to attract & hold heavy metals such as Lead and Cadmium.
  • Composting: containing waste so a natural decay and remediation process occurs.
  • Bio-augmentation: adding microbes & organisms to strengthen the same in waste to allow them to take over and decontaminate the area.
  • Bio-stimulation: the use of microbes designed to remove contamination applied in a medium to the waste.
  • Oilzapper & Oilivorous-S: oil spill treatment bacteria, feed on hydrocarbon compounds present in crude oil & oily sludge.





Contaminated waste is removed & transported to a processing site for treatment.

Ex situ bioremediation techniques:

  • Land-farming: turning contaminated soil for aeration & sifting to remove contaminants, or deliberately depleting soil of nitrogen to remove nitrogen-based organisms.
  • Bioreactor: the use of specially designed containers to hold the waste while bioremediation occurs
  • Windrows: rely on the periodic turning of piled polluted soil to enhance bioremediation by increasing degradation activities of indigenous and/or transient hydrocarbonoclastic bacteria present in polluted soil.
  • Biolpiling – It is a hybrid of composting & land farming.
Advantages Of Bioremediation:
  • Useful for destruction of a wide variety of contaminants + Can be carried out on-site, without disturbing normal activities + Less expensive & effective treatment.
Disadvantages Of Bioremediation:
  • Limited to only biodegradable compounds + Biological processes are often highly specific + Takes a longer time & consumes more area as well as water.

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 Career Development Program 2023 Result PDF     Download UPSC Mains 2023 Question Papers PDF  Free Initiative links -1) Download Prahaar 3.0 for Mains Current Affairs PDF both in English and Hindi 2) Daily Main Answer Writing  , 3) Daily Current Affairs , Editorial Analysis and quiz ,  4) PDF Downloads  UPSC 2022 Final Result🔥5 out of Top 10 from PW OnlyIAS Community. UPSC Prelims 2023 Trend Analysis cut-off and answer key