Geographical Perspective on Selected Issues and Problems

Air, water, land and noise pollution, urban waste, rural–urban migration with its push and pull, slums, and land degradation and its remedies.

Key ideas

Pollution is grouped by medium into air, water, land and noise pollution.
Air is polluted by burning coal, petrol and diesel, industry and mining; it harms the lungs, nerves and heart, and causes smog and acid rain.
Industry is the biggest human source of water pollution, with sewage and farm run-off; about a fourth of communicable diseases are water-borne.
Noise is measured in decibels; traffic is the biggest nuisance.
Uncollected urban waste breeds flies and rodents and releases methane as it rots; it can be turned into energy and compost.
People move from villages to cities for jobs (pull) and because of few jobs at home (push); migrants send remittances home.
Land degradation lowers the productivity of land; wastelands come from natural agents, human action or both, and watershed management helps restore them.

Remember

Waste uncollected	waste a day × per cent uncollected ÷ 100 (30–50% in many small towns; metros collect about 90%)
Waste produced	people × grams each a day ÷ 1,000,000 = tonnes
Water-borne cases	about one-fourth of communicable disease cases
Remittances in a year	monthly amount × 12
Urban by 2050	about 68% of the world’s people
Polluter pays	those who pollute bear the cost of cleaning up (the Daurala example)

Watch out

Forgetting that 1 tonne is 1,000,000 g when converting waste per person.
Calling gullies and desert sands human-made wastelands (they come from natural agents).
Measuring noise in hertz instead of decibels.

Worked example

Suppose a town of 20 lakh people produces 450 g of solid waste per person a day, and 50% is collected. How many tonnes are produced and how many left uncollected each day? (1 tonne = 1,000,000 g)

Working: 20 lakh × 450 ÷ 1,000,000; 50% of that

Answer: 900 tonnes produced; 450 tonnes uncollected