Page 130 - AI Ver 1.0 Class 9
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The different types of pollution are:
           •  Air Pollution: It is mixing of harmful gases in the air surrounding us that harm the health of humans, animals
          and plants. Human activities deplete the air quality and cause global warming and climate change of this mother
          Earth.
           • Water Pollution: It is contamination of water bodies like streams, rivers, oceans, etc. due to mixing of harmful
          chemicals rendering it toxic for plants and animals residing in these water bodies. This is a serious threat since
          70% of our earth is covered with water.
           • Soil Pollution: Soil is a mixture of both living and non living matter such as air, water, mineral and decaying
          organic matter. Soil Pollution is contamination of soil due to presence of pollutants or chemicals which are toxic
          for plants and animals living in that area. Some pollutants are naturally accumulated in soil due to precipitation.
          Some are accumulated due to human activities.


        Global Warming

        Global Warming is an increase in the average temperature of the earth mainly due to greenhouse gases (mainly
        carbon dioxide) produced by a lot of human activities. It has resulted in melting of glaciers, rising sea level and
        intense heat waves all across the globe. It is one of the major environmental issues as it creates an ecological
        imbalance and has become a reason for the extinction of many plant and animal species. Main causes of global
        warming are:



















           • Excessive use of fossil fuels like coal, oil and natural gas produces greenhouse gases-like methane, nitrous
          oxide and mainly carbon dioxide which trap the sun’s radiation within the atmosphere resulting in rise in global
          temperature.
           • Trees absorb CO  from the atmosphere and release oxygen instead, so they work as air purifiers. Deforestation
                          2
          due to urbanisation and industrialisation has reduced the number of trees on the earth. This has resulted in the
          increase of carbon dioxide level in the atmosphere.




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