Grammar improvements: Since 19 century, the environment has been polluted because of the fast development of industries and economics.
The first step to the development of the, the,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,
The main reason for the increase in the number of cases of cancer is the increase in the number of people who are exposed to air pollution.
The main cause of the increase in the number of cases of cancer is the increase in the number of people who are exposed to air pollution.
The main cause of the increase in the number of people who are exposed to air pollution is the increase in the number of industries and the increase in the number of people who are exposed to air pollution.
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