NCERT Solutions For Class 12 Geography Chapter 28 Geographical Perspective on Selected Issues and Problems

(i) (c) Yamuna

(ii) (b) Diarrhorea

(iii) (d) Air pollution

(iv) (a) Migration

(i) Water pollution is the contamination of natural water bodies, e.g., lakes, rivers, oceans, aquifers, groundwater, etc., by chemical, physical, radioactive or pathogenic microbial substances. The main sources of water pollution include industrial sources, agriculture source, domestic source, etc. Industrial waste is the most significant contributor of water pollution. Most of the industrial waste disposed off in rivers or lakes. Major water polluting industries are leather, pulp and paper, textiles and chemicals. Water pollution is a source of various diseases like diarrhoea, intestinal worms, hepatitis, etc. Sewage disposal, urban run-off, toxic effluents from industries, run-off over cultivated lands and nuclear power plants are important sources of water pollution.

Ganga and the Yamuna are among the most polluted rivers of India. Sources of Pollution in the Ganga and the Yamuna rivers are given in the table.

(ii) A slum is a heavily populated urban informal settlement characterized by substandard housing and environment. Slums are inhabited by migrate people who could not afford proper housing in the cities. Slums are residential areas of the least choice, poor hygienic conditions, poor ventilation; lack of drinking water, light and toilet facilities, etc. The poverty makes them vulnerable to drug abuse, alcoholism, crime, vandalism, escapism, etc. In India the total number of slum dweller are about 65 million, of which Maharashtra alone accounts for 11 million, Andhra Pradesh for 10 million, followed by West Bengal and Uttar Pradesh, with over 6 million each. Major problems of slums are:

• Poor Housing
• High Density of population
• Lack of water supply and drainage
• Poor transportation
• Power Shortage
• Poor Sanitation
• Environment pollution like air, water, etc.
• Poor health and related problems like malnutrition, communicable diseases, alcoholism, crimes, etc.

(iii) Land degradation is either as a temporary or a permanent decline in productive capacity of the agricultural land. Deforestation, overgrazing, excessive use of fertilizers and pesticides, industrialisation, urbanisation, etc., are main causes of land degradation. The total land area of India is 329 million hectares of which about 178 million hectares (54%) is converted into wastelands for one or other reasons. Following are some practices for controlling land degradation.

• Strip farming reduces soil erosion from wind and water.
• Contour strip cropping reduces soil erosion and protects water quality
• Crop rotation can reduce soil erosion on their land.
• Soil erosion can be prevented by formation of ridge and furrow during irrigation.
• Construction of check dams can reduce the velocity of runoff.

(i) Pollution is the process of making land, water, air or other parts of the environment unsuitable to use. A pollutant is a substance that pollutes the air, water, land, etc.

(ii) Combustion of coal, petrol and diesel, insecticides, pesticides, fertilizers, industrial processes, solid waste disposal, sewage disposal, etc., are major sources of air pollution.

(iii) Urban waste disposal is a serious problem in India. Fast increasing urban waste and lack of arrangements of urban waste disposal in most of the cities are associated with urban waste disposal. About 50% of the urban wastes are left uncollected in open spaces between houses and in wastelands leading to serious health hazards.

(iv) Air pollution causes various diseases related to respiratory, nervous and circulatory systems like irritation to the eyes, nose and throat, bronchitis, pneumonia, headaches, nausea, allergic reactions, asthma, emphysema, lung cancer, heart disease, and even damage to the brain, nerves, liver, or kidneys.