(i) Air is called breath of life because it contains
oxygen, which is required by all living organisms for respiration.
(ii) Causes of air pollution are
(a) The major cause of air-pollution is burning of fossil fuels like coal and petroleum, which releases different oxides of nitrogen, sulphur, etc., in the air that are harmful for atmosphere.
(b) Emission from thermal power plants and industries.
Effects of air pollution are
(a) It affects the respiratory system and causes diseases like cold, asthma, lung cancer and - pneumonia.
(b) Pollutant gases cause allergies, irritation in eyes and lungs, etc.