Read the passage and answer the questions:
Pollution
Water pollution is a source of various water-borne diseases like diarrhoea, intestinal worms, hepatitis. Air pollution also causes various diseases related to respiratory, nervous and circulatory systems. Smoky fog over cities called as urban smog is caused by atmospheric pollution. Rainwater analysis of urban environment has indicated that pH value of the first rain after summer is always lower than the subsequent rains. Urban waste disposal is a serious problem in India. In metropolitan cities like Mumbai, Kolkata, Chennai, Bengaluru, etc., about 90 per cent of the solid waste is collected and disposed. But in most of other cities and towns in the country, about 30 to 50 per cent of the waste generated are left uncollected which accumulate on streets, in open spaces between houses and in wastelands leading to serious health hazards. These wastes should be treated as resource and utilised for generating energy and compost. Untreated wastes ferment slowly and release toxic biogas to the atmosphere, including methane. Based on the universal law ‘Polluter pays’ effort to restore the ecology and safeguard the human health with people’s participation has taken place in Daurala near Meerut. At national level the first major legislative provision to address pollution was the Water Prevention and Control of Pollution Act 1974 followed by Environment Protection Act, 1986.
Smog is caused by _______________.
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) → air pollution
Option (1) water pollution — Incorrect. Water pollution fouls rivers, lakes and groundwater, not the air over a city.
Option (2) air pollution — Correct. Combustion of fossil fuels, mining and industries add dust, fumes, smoke and gases to the air. Smoky fog over cities, called urban smog, is caused by this atmospheric pollution.
Option (3) solid waste disposal — Incorrect. Solid waste piles up on the ground; smog is a haze in the air.
Option (4) noise pollution — Incorrect. Noise is unwanted sound; it forms no fog.
NCERT (2025-26): “Air Pollution … Air pollution is taken as addition of contaminants, like dust, fumes, gas, fog, odour, smoke or vapour to the air in substantial proportion and duration that may be harmful to flora and fauna and to property. With increasing use of varieties of fuels as the source of energy, there is a marked increase in emission of toxic gases into the atmosphere resulting in the pollution of air. Combustion of fossil fuels, mining and industries are the main sources of air pollution.…” “Air Pollution … Smoky fog over cities called as urban smog is caused by atmospheric pollution. It proves very harmful to human health. Air pollution can also cause acid rains. Rainwater analysis of urban environment has indicated that pH value of the first rain after summer is always lower than the subsequent rains.…” |