None can live without air. Fresh air is needed to keep fit. But the air is being polluted in many ways. Air pollution is generally caused by smoke. Man makes fire to cook food, make bricks, burn refuse, and melt pitch; the fire creates smoke and thus pollutes the air. Railway engines, Powerhouses, mills, and factories use coal and oil.
Industries make use of many chemicals. Automobiles use petrol and diesel oil. When these fuels and chemicals burn. They create smoke, which pollutes the air. All kinds of smoke pollute the air and create health problems. The most serious air contamination happens in large modern regions where human existence is undermined by different lethal illnesses.