Saturday , August 15 2020

NCERT 8th Class (CBSE) Science: Pollution of Water and Air

Question: What is Ozone hole or depletion of ozone layer?

Answer: A gas named ozone forms a protective layer around the atmosphere of the earth. It protects the earth from the ultraviolet rays of the sun. But some chemicals used in refrigeration causes damage to this layer. CFCs (Chloro Fluoro carbon) cause tearing away of this layer. This is called depletion of ozone layer. At some points, this layer is depleted completely and holes are created. These holes are called ozone holes.

Question: What steps has honourable Supreme Court taken to save the Taj Mahal from air pollution?

Answer: The Supreme Court has given orders that cleaner fuel be used in the near about areas of the Taj Mahal. Fuels like CNG and LPG are considered clean fuel. Moreover petrol should be free from lead. This is called unleaded petrol. Only unleaded petrol can be used in areas near the Taj Mahal.

Question: Explain Ganga Action Plan.

Answer: Ganga Action Plan or GAP was launched by the Government of India in April 1985 to reduce water pollution in the river Ganga. Despite heavy investments towards cleaning the Ganga, pollution levels have not reduced and is as terrifying as before. Crores have been spent on the project but the pollution levels in Ganga are as high as ever. Till 1993, the Government said that the project had been successful. But then, Sankat Mochan Foundation, Varanasi, started doing water testing and it was clear that sewage was still flowing into the river. According to environmentalists, about 90% of pollution into the holy river is caused by sewage generation, while about 5-6% can be blamed on bathing and other activities. The programme was launched with much fanfare, but it failed to decrease the pollution level in the river.

Question: What is responsible for destroying the beauty of the Taj? What measures are being taken to save it?

Answer: The Taj Mahal is famous for its white beauty. It is considered as one of the seven wonders of the world. But there is a great threat to the beauty of this wonder. Air pollution has started showing its effect on the Taj Mahal. The colour of the white marble has started to fade and is getting corroded. All this is being caused due to sulphur dioxide and nitrogen dioxide emitted by Mathura Oil Refinery and other rubber processing, automobile, chemical industries working in and around Agra. Corrosion or marble cancer is caused due to acid rains. Acid rains are caused beacuse the acids of sulphur and nitrogen mix with rain water.

Various measures are being taken to save the beauty of the Taj Mahal. The Supreme Court of India has ordered the Industries to switch over to cleaner and pollution free fuels. Automobiles have been ordered to use CNG and LPG as the fuel. Unleaded petrol will only be made available to be used as fuel in vehicles.

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