Due to the increase in the human population over the years, there has been a rise in the demand for food, water, home electricity, roads, and other commodities which are essential for human existence. These demands lead to overexploitation of natural resources and also cause air, soil, and water pollution. The human population is solely responsible for this and has a moral obligation to look for possible solutions. Environmental issues are one of the very important concepts in class 12. 

The students preparing for class 12 exams can access the course material related to Maths, Chemistry, Physics, and Biology on the Msgvo app. It is a learning app that makes studying complex subjects easy and enables students to study on the go. The course material is designed in such a way that students can understand the science behind each concept. They can study anytime and anywhere, based on their convenience. The Msgvo app provides an interactive learning experience and builds the problem-solving skills of the students. The app has detailed lesson plans which help students to understand the concepts easily and improve their performance. 

The following topics and subtopics are covered on Environmental Issues which would enable the students to clarify their doubts:

1. Air pollution and its control
   Air Pollution means the presence of harmful chemicals and poisonous compounds in the air, which can cause serious health ailments in adults and children. It also has an adverse effect on crops and plants. It is commonly caused by the following:
   1. Smokestacks of thermal plants, shelters release tiny particles of dust and soot. They also release several types of gases such as carbon monoxide, sulfur dioxide, nitrogen, and oxygen. The pollutants must be filtered out or separated before releasing into the atmosphere. Electrostatic Precipitator is one such equipment that uses electrical energy to remove solid and liquid impurities from air released by the smokestack. 
   2. Another major cause of air pollution is Automobiles.  
2. Water pollution and its control
   Water pollution is the presence of harmful containments in water bodies that make them unfit for consumption. Over the years, the human population has dumped household and industrial waste into water bodies. The Government of India has passed the Water (Prevention and Control of Pollution) Act 1974 to protect water resources. Water pollution is caused by:
   1. Domestic waste contains biodegradable organic matter which is decomposed by bacteria and other micro-organisms present in the water bodies. The level of biodegradable organic matter in sewage water can be calculated through Biochemical Oxygen Demand (BOD). Sewage waste contains several pathogenic micro-organisms that can cause serious diseases like typhoid and dysentery. 
   2. Some of the toxic substances which are present in the industrial waste might lead to the Biomagnification of the aquatic food chain. 
   3. The waste dumped in to the water bodies might increase the natural aging process of the water bodies. This is known as Cultural or Accelerated Eutrophication.
3. Solid Wastes
   Solid waste generally contains food waste, paper wastes, textile, and rubber wastes from households and industries. These types of waste are generally partially burnt and the remaining is dumped in open areas which often become breeding grounds for rats and flies. Sanitary landfills are a better alternative to open area dumps. 
   1. The solid waste produced by hospitals is quite dangerous as it contains harmful chemicals, disinfectants, and other pathogens.
   2. Electronic waste or e-waste should be recycled in an environment-friendly manner. 
4. Agro-Chemicals and their Effects
   Green Revolution has resulted in excessive use of inorganic fertilizers and pesticides to increase crop yield. But the increased usage could lead to Eutrophication of the aquatic system. We need to adopt Integrated Organic farming where waste from one product is utilized as nutrition for another. 
5. Radioactive Wastes
   Although nuclear energy was considered an environment-friendly way of generating electricity, it has its share of cons. The first major problem is that of accidental leakage and the second is the disposal of radioactive waste. Such type of waste yields radiation which can cause serious damage to organisms. 
6. Greenhouse Effect and Global Warming
   The greenhouse effect is a condition when the heat from the Sun gets trapped in the Earth's atmosphere and heats the surface. Greenhouse gases absorb long-form radiation from the Earth and emit it back towards Earth. A rise in Greenhouse gases has resulted in Global Warming and to control this, humans need to stop deforestation, reduce the use of fossil fuels and look for renewable sources of energy.
7. Ozone Depletion in the Stratosphere
   The layer of Earth’s atmosphere that is located between the troposphere and mesosphere is called the Stratosphere. It filters out the Sun’s Ultraviolet (UV) Radiation. The thickness of the Ozone is measured in terms of Dobson Units (DU). The ozone layer is constantly formed by the UV rays and also depleted into molecular oxygen in the stratosphere. But the balance has been disturbed due to the presence of chlorofluorocarbons (CFCs) which has resulted in thinning of the Ozone layer over the Antarctic region known as the Ozone Hole.
8. Degradation by Improper Resource Utilisation and Maintenance
   The natural resources become degraded due to improper Utilisation and maintenance:
   1. Soil erosion is a phenomenon when the topsoil of land is eroded by water and wind. This happens due to activities like over-cultivation, unrestricted grazing, and poor irrigation. 
   2. When large barren lands are left unsupervised for a long time, it leads to the creation of a desert. This phenomenon is known as desertification. 
   3. Irrigation without proper drainage of water results in Waterlogging which in turn brings salt to the surface of the soil. Waterlogging and soil salinity affect the quality and crop yield. 
9. Deforestation and Reforestation
   Deforestation is the decline in forest areas around the world due to factors such as urbanization and the clearing of forests for agricultural use. In northeastern states of India, slash and burn agriculture, also known as Jhum cultivation has resulted in massive deforestation. Reforestation means planting trees in areas where excessive deforestation has taken place. Chipko movement was one such initiative. The Government of India has launched programs like Joint Forest Management (JFM) to reinforce reforestation.
   Thus, these are the important environmental issues relating to environmental pollution and the degradation of natural resources. To understand the topic better, watch the learning videos available on the Msgvo app which has over 15,000 videos relating to Maths, Chemistry, Physics, and Biology. The Msgvo app is an NCERT solutions app that makes a student exam-ready through its CBSE and ICSE based course material.