𝗘𝗻𝘃𝗶𝗿𝗼𝗻𝗺𝗲𝗻𝘁𝗮𝗹 𝗣𝗼𝗹𝗹𝘂𝘁𝗶𝗼𝗻
Environmental pollution can therefore be defined as any undesirable change in the physical, chemical or biological

characteristics of any component of the environment (air, water, soil), which can cause harmful effects on various forms of life or property. Environmental pollution could be of different types:
•Air Pollution
It is an atmospheric condition in which certain substances are present in concentrations that can cause undesirable effects on man and his environment. These substances include gases, particulate matter, radioactive substances, etc. 

Causes of Air Pollution

1. Natural sources of air pollution are volcanic eruptions, forest fires, biological decay, etc. 
2. Man-made sources also lead to air pollution man-made sources include thermal power plants, industrial units, vehicular emissions, fossil fuel burning, etc. 
   3 The most important indoor air pollution is radon gas. Radon gas and its radioactive daughters are responsible for a large number of lung cancer deaths each year. 

• Control of air pollution
  Air pollution can be minimized by the following methods:

1. Use public transport systems, bicycles, etc. 
2.  Using non-conventional sources of energy. 
3. Planting more trees
4. Vehicular pollution can be checked by regular tune-ups of engines, replacement of more polluting old vehicles, and installing catalytic converters. 
5. Shifting to less polluting fuels, hydrogen gas. 
6. Use low-sulfur coal in industries. 
   •Noise Pollution
   We hear various types of sounds every day. A type of sound may be pleasant to someone and at the same time unpleasant to others. The unpleasant and unwanted sound is called noise. There  is a wide range of sound pressures that encounter the human ear. Increased sound pressure does not invoke a linear response in the human ear. A meaningful logarithmic has been devised. The noise measurements are expressed as sound pressure level (SPL) 
   which is the logarithmic ratio of the sound pressure to a reference pressure. It is expressed as a dimensionless unit, the decibel (dB). A decibel scale is a measure  of loudness. Noise can affect the human ear because of its loudness and frequency (pitch). 

• Sources of Noise Pollution

1. The main sources of noise pollution are various modes of transportation like air, road, and rail transportation. 
2. The industrial operations also lead to noise pollution. 
3. Construction activities and electric home appliances  also cause noise pollution. 
4. Loudspeakers have also been a major cause of noise pollution. 

• Control of Noise Pollution

1. Sources of noise pollution like heavy vehicles and old vehicles may not be allowed to ply in the populated areas. 
2. Noise-making machines should be kept in containers with sound-absorbing media; the noise path will be interrupted and will not reach the workers. 
3. Planting more trees with broad leaves. 
4. Silencers can reduce noise by absorbing sound; for this purpose, various types of fibrous material could be used. 
5. Legislation can ensure that sound production is minimized at various social functions. Unnecessary horn blowing should be restricted, especially in vehicle-congested areas. 
6. It also leads to behavioral change. Increase stress level. According to scientific research, people living near the roadside are prone to having more stress and also have behavioral change. 
   •Water Pollution
   Water pollution can be defined as the aliteration and physical,chemical or biological characteristics of water making it unsuitable for designated use in its natural state. 

• Causes of Water Pollution

1. Pollution of water can be caused by point sources or nonpoint sources point sources are specific sites near water that directly discharge effluents into them. Major point sources of water pollution are industries, power plants, underground coal mines, offshore oil wells, etc. 
2. The discharges from non-point sources, not any particular site, of the source are scattered, which individually or collectively pollute water. Surface runoff from agriculture fields, overflowing small drains, rainwater sweeping roads and fields, atmospheric deposition, etc. are the nonpoint sources of water pollution. 

• Thermal Pollution
  Thermal pollution can be defined as the presence of waste heat in the water, which can cause undesirable changes in the natural environment. 
• Causes of Thermal Pollution

1. Heat-producing industries that are thermal power industries, nuclear power industries, refineries and still mining, etc. 
2. Power points only utilize 1/3 of the energy provided by the fossil fuels for
    their operation. The remaining 2/3 is lost as heat to cooling water.
3. Cold water is generally drawn from the nearby water body past through the plant and returns to the same water body with a temperature 10–16 °C higher than the initial temperature. Excess heat reaching such bodies causes thermal pollution of water. 

• Control of Thermal Pollution

1. Cooling Ponds: Water from condensers is stored in a pond where natural evaporation cools the water, which can be recirculated or discharged in nearby water bodies. 
2. Spray pond: Water from the condenser is received in spray. Here  the water is sprayed through noozels and
    where fine droplets are formed. Heat from these fine droplets is dissipated to the atmosphere.
   3.Cooling towers:
   Wet cooling towers: Hot water is sprayed over baffles. Cool air entering from the sides takes away the heat and cools the water. 
   Dry cooling tower: The heated water flows in a system of pipes. Air is passed over these hot pipes through fans. There is no water loss in the method. 
   •Soil Pollution
   Soil pollution is the presence of chemical and harmful substances in the soil at a higher level than the normal level, which negatively effects the environment and the soil. 
   Causes of Soil Pollution
   1 Excessive use of fertilizers leads to soil pollution. 
3. Dumping or disposing of waste whether it is human waste, industrial waste or animal waste all of them lead to soil pollution. 
   Poor management of waste or improper management of waste also leads to soil pollution. 
4. Sewage produced in urbanized areas can also contaminate the soil.
5. Use of chemical pesticides that contain various hazardous substances.
   6: Excessive use of these pesticides can lead to severe soil pollution. 

• Control of soil pollution
  1: Using organic fertilizers and biopesticides instead of the chemical ones. 
  2: Prevent soil erosion  by planting trees on barren slopes.                 3. Cow dung should be used for methane  production.                        4. Soil waste should be properly collected and should be disposed of using the appropriate method.
  These were the key types of environmental pollution.