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Atmospheric pollution raises problems of several types. First, there are local problems due to the production of smoke and offensive gases by factories.
Secondly, there are regional problems created by industrial agglomerations which may spread the same harmful effects over whole areas.
Thirdly, there are some types of pollution, such as those arising from nuclear explosives, which cover a considerable portion of the globe.
And lastly, there appeared one more type of pollution which is threatening the globe as a whole.
Recent scientific research suggests that the protective layer of ozone around our planet is under severe attack.
Alarm bells were sounded in 1982 when researchers in the Antarctic first identified a yawning hole over the Antarctic where the ozone layer is thinnest.
The major cause of this weakening of the ozone layer is believed to be the increasing amount of harmful chemicals that are being released into the atmosphere by humankind.
Environmentalists and scientists point out that a further one per cent drop in the overall ozone layer can cause an increase of skin cancer.
The appearance of the Antarctic hole has intensified the search for a cause. Strong evidence now suggests that it is the growing industrial use of chlorine compounds called chlorofluorocarbons (CFCs) which is responsible. CFC is a propellent gas commonly used in aerosol sprays, air cooling systems in fridges and air-conditioning.
Researchers suggest that the level of CFCs in the atmosphere is actually increasing by 5 per cent each year.
Since 1969 the ozone level has fallen by 3 pen cent over the densely populated cities of the US, Canada and Europe and by 4 per cent over Australia and New Zealand.
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