The term ‘pollution’ refers to unfavourable alteration to our surroundings, wholly or largely as a by-product of human’s action through direct and indirect effects of changes in energy pattern, chemical and physical construction and abundance of organisms. Thus, it is the addition of any foreign material to water, air or soil, which may change immediately or after some time, the natural properties of these basic constituents further causing some unfavourable change by making them unfit and injurious. Industrialization, poverty, population-explosion, urbanization, over-exploitation of resources, etc. are some of the factors which have contributed to environmental deterioration.

The Royal Commission on Environmental Pollution in U.K. in its third report gave the following definition to the term “Pollution”, namely:

The introduction by man into the environment of substances or energy liable to cause hazards to human health, harm to living resources and ecological systems, damage to structure or amenity or interference with legitimate uses of the environment.

Water is one of the renewable resources essential for sustaining all forms of life, food production, economic development, and for general well being. It is impossible to substitute for most of its uses, difficult to de pollute, expensive to transport, and it is truly a unique gift to mankind from nature. Water is also one of the most manageable natural resources as it is capable of diversion, transport, storage, and recycling. All these properties impart to water its great utility for human beings.

Water pollution is the contamination of water bodies (e.g. lakes, rivers, oceans, aquifers and groundwater). Water pollution occurs when pollutants are discharged directly or indirectly into water bodies without adequate treatment to remove harmful compounds.

• Natural sources- clay & slit from soil erosion, leaching of minerals, falling of organic matter from banks.
• Man-made sources
  1. municipal waste water
  2. industrial waste water
  3. domestic sewage
  4. surface run off (contain pesticides & fertilizers)

• Raw sewage running into lake or streams
• Industrial waste spills contaminating groundwater
• Radiation spills or nuclear accidents
• Illegal dumping of substances or items within bodies of water
• Biological contamination, such as bacteria growth
• Farm runoff into nearby bodies of water

These kinds of environmental pollution are linked to health issues in humans, animals and plant-life.

• Biodegradation of domestic sewage
• Suspended, solid particles & inorganic material can be removed by use of filter
• Industrial effluents under various treatments to lower pollutants rate
• Any type of waste material does not discharge into water bodies
• Agriculture runoff water should be minimized
• In industry there must be a water treatment plant

Indian Council for Enviro-Legal Action v. Union of India ¹⁾

The petitioner, the Indian Council for Enviro-Legal Action filed a writ to prohibit and remedy the pollution caused by several chemical industrial plants in Bichhri village, Udaipur District, Rajasthan. The Respondents operated heavy industry plants there, producing chemicals such as oleum (a concentrate form of sulphuric acid), single super phosphate and the highly toxic “H” acid (the manufacture of which is banned in western countries). Respondents operated these plants without permits which caused serious pollution of the environment.

The court held that the Central Government should consider treating chemical industries separately from other industries, and closely monitoring them to ensure they did not pollute the environment. Establishing environmental courts was a good suggestion and would ensure that environmental matters were given the constant and proper consideration they deserved.

Court further ordered the respondent industries to pay Rs. 37,385,000 INR together with a compound interest of 12 percent per annum until the sum would have been fully paid or compensated. In addition to this, the respondent industries were mandated to pay the litigation fees for deliberately wasting the court’s time and resources, as the case was carried on for nearly fifteen years, long after the Court’s final decision and for all these years the applicants were forced to carry on the case.

Air contains a mixture of various gases like oxygen, nitrogen, carbon dioxide, argon etc. Air pollution is the introduction into the atmosphere of chemicals, particles, or biological materials that cause discomfort, disease, or death to humans, damage to other living organisms such as food crops, natural environment or built environment.

According to the dictionary, air pollution is the contamination of air by smoke and harmful gases, mainly oxides of carbon, sulphur, and nitrogen.

The major sources of air pollution are:

• Industrial emissions
• Vehicular emissions
• Domestic emissions

The most common air pollutants in urban areas include Sulphur dioxide (SO2), Nitrogen oxides (NO & NO2), Carbon monoxide (CO), etc. Apart from this, the gases discharged from refrigerators, air conditioners etc. are responsible for depletion of the Ozone layer.

Some examples of air pollution include:

• Exhaust fumes from vehicles
• The burning of fossil fuels, such as coal, oil, or gas
• Harmful off-gassing from things such as paint, plastic production, and so on
• Radiation spills or nuclear accidents
• Air pollution is linked to asthma, allergies and other respiratory illnesses.
• Combustion (of natural gas, petroleum, coal & wood in industries, automobiles, aircrafts etc.)
• Metallurgical processing (mineral dust, fumes containing fluorides, sulphides etc.)
• chemical industries
• processing industries(like cotton textiles, wheat flour mills)
• welding, stone crushing etc

Much evidence links air pollutants to respiratory & other diseases in humans

Examples of air pollution-related diseases:

• Pulmonary irritation & impaired lung function:
  • chronic bronchitis
  • emphysema
• Cancer
• Systemic toxicity:
  • Lead
  • Mercury
  • Increased susceptibility to disease.

• Wild & domestic animals probably affected in the same ways as humans.
• Plants damaged by ozone, sulfur dioxide, & acids:
  • ozone - weakens pine needles & makes them more susceptible to insects & diseases
  • sulfur dioxide - suppresses growth
  • acid - damages leaves & needles & also removes nutrients

• Critical [PM10 > 90 µg/m3] :Guwahati, Patna, Raipur, Delhi, Faridabad, Dhanbad, Nagpur, Bhopal, Indore, Jalandhar, Ludhiana, Jaipur, Howrah, Kolkata
• High [PM10 61 - 90 µg/m3] : Hyderabad, Chandigarh, Ahmedabad, Panjim, Shimla, Bangalore, Mumbai, Pune, Bhubanshwar
• Moderate [PM10 31 - 60 µg/m3] : Kochi, Shillong, Chennai
• Low [PM10 up to 30 µg/m3] : Aizwal

• The judiciary has taken strong note of the deteriorating environmental conditions in Delhi in response to public litigations. One of the earliest such instances was the judgement passed by the Supreme Court of India to deal with the acute problem of vehicular pollution in Delhi in response to a writ petition filed in 1985. Subsequently, it ordered the shutdown of hazardous, noxious industries and hot-mix plants and brick kilns operating in Delhi.
• Delhi Vehicle Ban: In 2015, the National Green Tribunal (NGT) had banned the plying of petrol vehicles older than 15 years and diesel vehicles older than 10 years in the national capital region (NCR). It also banned the parking of 15-year-old vehicles in any public area. This decision was challenged before the Hon'ble Supreme Court. The Supreme court endorsed the NGT order and directed that such vehicles be impounded.

• Save energy: Making electricity in conventional power plants generates pollution, so anything you can do to save energy will help to reduce pollution (and global warming as well). Switch to low-energy lamps, use a laptop computer instead of a desktop, dry your clothes outdoors, and heat insulate your home. Use an electricity monitor to help identify your most inefficient appliances.
• Save water when you can: Producing cool, clean water needs huge amounts of energy so cutting water waste is another good way to save energy and pollution.
• Avoid using car for short travel: Sometimes we have to use cars, but often we can get a bus or a train or (for shorter distances) walk or cycle. Cars are now the biggest source of air pollution in most urban areas, so traveling some other way through a town or city helps to keep the air clean. When you have to use your car, drive efficiently to save fuel and money, and cut pollution. It's particularly important to avoid car use when smog is bad in your city.
• Never burn household waste: If you burn plastic, you release horrible toxic chemicals into the local environment, some of which can be sucked up your own nose.
• Garden organically: Spray of pesticide in the garden is a dangerous act. We can tackle virtually all garden pests and diseases in more environmentally friendly organic ways. Buying or growing organic food is a good option.
• Reduce use of chemicals: Spray of an air freshener is a choking with chemical pollution. Try to be natural and healthy.
• Use water-based paints and glues: The nasty solvents in paints, varnishes, and wood preservatives should be avoided.
• Reduce, reuse, and recycle: Buying new stuff is fun, but reusing old things can be just as good.
• Don't smoke: Cigarettes contain addictive chemical called nicotine that makes you want to go on smoking them. They cause all kinds of health problems, but they also cause much localized air pollution.

The word ‘noise’ originated from the Latin word ‘nausea’ meaning sea-sickness. ‘Noise’ is any unwanted sound that disrupts environmental equilibrium. Noise is measured in decibels. A major source of ‘noise’ is by motor vehicles, aircrafts, fire-crackers, sirens, loud speakers and machinery.

According to a survey conducted by the National Physical Laboratory, Delhi, Mumbai and Kolkata are amongst the noisiest cities in the world. Noise pollution has harmful effects on the environment, humans and animals. Some adverse effects of noise pollution on human health are:

• Hearing loss or hearing impairment;
• Rise in blood pressure;
• Cardio-vascular health effects;
• Increase in stress level; and
• Decrease in efficiency and concentration

Noise pollution is excessively displeasing to humans, animals, or we can say that machine-created environmental noise disrupts the activity or balance of human or animal life. Poor urban planning may give rise to noise pollution, since industrial and residential buildings constructed side-by-side can result in noise pollution in the residential areas.

Noise pollution is any loud sounds that are either harmful or annoying to humans and animals. Some examples of noise pollution:

• Airplanes, helicopters, and motor vehicles
• Construction or demolition noise
• Human activities such as sporting events or concerts
• Noise pollution can be disruptive to humans' stress levels, may be harmful to unborn babies, and drives animals away by causing nervousness and decreasing their ability to hear prey or predators.
• Various industries such as textile mills, printing presses, engineering establishments.
• Agriculture machines like tractors, harvesters, tube wells etc.
• defence equipments such as tanks, shooting practices, explosions.
• transport vehicles
• Public address systems like loud speakers.
• dynamite blasting
• cracker used at occasions like marriages & festivals
• Stone crushing, construction work etc.

• Decibels meters
• Noise pollution control laws
• Green mufflers or green belt vegetation
• Ear plugs & ear muffs
• Permissible time & sound level for use of crackers
• Sound diversion

In this case the court stressed that in the modern days noise had become one of the major pollutants and it had serious effects on human health. It emphasized that those who made noise often took shelter behind Article 19(1)(a) pleading freedom of speech and right to expression. However, it was of the view that freedom from noise pollution was a part of the right to life under Article 21 of the Constitution. Indian judicial opinion had been uniform in recognizing right to live in freedom from noise pollution as a fundamental right protected by Article 21 and noise pollution beyond permissible limits as an in-road on that right. The Supreme Court agreed with this view. Noise interfered with the fundamental right of the citizens to live in peace and to protect themselves against forced audience.

In conclusion, the court directed, inter alia, that the Department of Explosives (DOE) had to come out with the chemical formulae for each type or category or class of firecrackers. There would be a complete ban on bursting sound emitting firecrackers between 10 pm and 6 am. Every manufacturer on the box of each firecracker had to mention details of its chemical contents. The noise level at the boundary of the public place, where loudspeaker or any other noise source was being used would not exceed 10 dB(A) above the ambient noise standards for the area. No one was allowed to use any sound amplifier at night (between 10. 00 p.m. and 6.a.m.) except in public emergencies. No vehicular horn should be allowed to be used at night (between 10 p.m. and 6 a.m.) in residential area except in exceptional circumstances.

Deforestation, release of toxic substances on the land, throwing of unhygienic waste on earth, dumping of garbage, biomedical waste etc. causes land pollution. Excessive use of pesticides is also a source of land pollution as this effects the potability of water.

Wastes are the materials that are not needed and are economically unusable without further processing. ‘Solid wastes’ includes agricultural wastes, ashes, bio-medical wastes, body parts of dead animals, dry or wet garbage from domestic activities which may contain plastics, metals, woods, glass, paper, detergents, industrial wastes, mining wastes etc.

All living beings require food to obtain energy from which they carry on their daily activities. If the food consumed is polluted or adulterated it will have injurious effects on the consumer’s health. The pollution of food begins by use of chemical fertilizers and various pesticides at different stages of plant growth. These chemicals directly or indirectly affect the quality of food and affects health of the consumer. Food also gets polluted during processing, storage, packaging and transportation.

Temperature plays an important role in determining the conditions in which living organisms can survive. Any undesirable, harmful change in natural temperature disturbing the natural heat balance of the surroundings is called ‘Thermal Pollution’.

Thermal pollution is the increase of temperature caused by human activity. A few examples of this include:

• Warmer lake water from nearby manufacturing (using cool water to cool the plant and then pump it back into the lake)
• increase in temperatures in areas with lots of concrete or vehicles, generally in cities.

These kinds of environmental pollution can cause aquatic life to suffer or die due to the increased temperature, can cause discomfort to communities dealing with higher temperatures, and will affect plant-life in and around the area.

One of the most important and dangerous types of pollution is ‘nuclear pollution’. ‘Nuclear pollution’ is produced by nuclear explosion which are carried out for performing nuclear tests and which is further used for making nuclear weapons. Due to these explosions about 15 to 25% of the radioactive particles enter into the atmosphere. Once they enter into the atomsphere they continue to fall on the earth for several years. The best example is the Hiroshima Atomic Bombings.

There are many causes for pollution.

• Air pollution can be caused by both human and anthropogenic sources.
• The main contributors for air pollution are human-made pollutants due to activities like combustion, construction; mining, agriculture and warfare are significant.
• Emissions from motor vehicles are one of the leading causes of air pollution.
• pollution sources that are stationary include chemical plants, coal-fuelled power plants, petrochemical plants, oil refineries, nuclear waste disposal, large live stock farms, incinerators, factories producing PVC, metals, plastics and other heavy industry.
• Pollution from agriculture comes from clear felling, burning and spraying of pesticides and herbicides. Humans are the primary cause of global warming since 1950s.
• Soil contaminants include chlorinated hydrocarbons, heavy metals, solid hospital wastes, lead, and fuel. Ordinary landfills are the source of chemical substances entering the soil environment.
• Water pollution can be caused by discharge of toxic pollutants like pesticides, heavy metals and non-degradable chemical compounds into fresh or ocean waters.
• The sources of these can be industries, chemical, heavy metal, hospital wastes. They also can be untreated or partially treated sewage water.

Pollutants are substance or energy which when introduced into the environment causes undesired effects or adverse effects on useful resources. These pollutants may be gases, liquids, solids or high pitched sounds. Gaseous pollutants are produced during the manufacturing process by most industries. Gaseous pollutants are also emitted by vehicles and burning of fuel and other substances. Some of the common gaseous pollutants are carbon monoxide, carbon dioxide, sulphur dioxide, hydrogen sulphide, hydrogen cyanide, ammonia gas.

The control of the emission of various particulates into the environment so as to bring down the level of the pollution is termed as pollution control. The main steps that can be followed in this regard include recycling and reusing the products that can be used a few times so that the waste produced from them does not deplete the environment.Paper bags can be used instead of plastic carry bags. Also the waste water that is to be thrown into the water bodies from the industries should be treated first to bring down its hazardous nature which poses a threat to the aquatic natural species.

Moreover the amount of raw material that is to be used should be used in an adequate quantity so that it results in low generation of the waste amount which is mixed with the environmental agents later. Apart from these, proper noise and smoke precipitators should be used to bring down the amount of lethal smoke and noise produced to help protect the environment.