RELAXATION SCIENCE

 Controlling Vehicular Air Pollution: A Case Study of Delhi   With its very large population of vehicular traffic, Delhi leads the country in its levels of air-pollution – it has more cars than the states of Gujarat and West Bengal put together.  In the 1990s, Delhi ranked fourth among the 41 most polluted cities of the world.  Air pollution problems in Delhi became so serious that a public interest litigation (PIL) was filed in the Supreme Court of India.  After being censured very strongly by the Supreme Court, under its directives, the government was asked to take, within a specified time period, appropriate measures, including switching over the entire fleet of public transport, i.e., buses, from diesel to compressed natural gas (CNG).  All the buses of Delhi were converted to run on CNG by the end of 2002.  You may ask the question as to why CNG is better than diesel. The answer is that CNG burns most efficiently, unlike petrol or diesel, in the automobiles and very little of it i

  😎 HUMAN EXCRETORY SYSTEM  😎  In humans, the excretory system consists of a pair of kidneys, one pair of ureters, a urinary bladder and a urethra.  Kidneys are reddish brown, bean shaped structures situated between the levels of last thoracic and third lumbar vertebra close to the dorsal inner wall of the abdominal cavity.  Each kidney of an adult human measures 10-12 cm in length, 5-7 cm in width, 2-3 cm in thickness with an average weight of 120- 170 g. Towards the centre of the inner concave surface of the kidney is a notch called hilum through which ureter, blood vessels and nerves enter.  Inner to the hilum is a broad funnel shaped space called the renal pelvis with projections called calyces.  The outer layer of kidney is a tough capsule.  Inside the kidney, there are two zones, an outer cortex and an inner medulla.  The medulla is divided into a few conical masses (medullary pyramids) projecting into the calyces (sing.: calyx).  The cortex extends in between the A diagrammati

 SOLID WASTES  Solid wastes refer to everything that goes out in trash.  Municipal solid wastes are wastes from homes, offices, stores, schools, hospitals, etc., that are collected and disposed by the municipality.  The municipal solid wastes generally comprise paper, food wastes, plastics, glass, metals, rubber, leather, textile, etc.  Burning reduces the volume of the wastes, although it is generally not burnt to completion and open dumps often serve as the breeding ground for rats and flies.  Sanitary landfills were adopted as the substitute for open-burning dumps.  In a sanitary landfill, wastes are dumped in a depression or trench after compaction, and covered with dirt everyday.  Landfills are also not really much of a solution since the amount of garbage generation specially in the metros has increased so much that these sites are getting filled too.  Also there is danger of seepage of chemicals, etc., from these landfills polluting the underground water resources.  A solution t