The graph below shows the pollution levels in London between 1600 and 2000.

Given is a line graph illustrating the level of

sulphur

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dioxide and

Smoke

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per cubic metre in London from 1600 to 2000.

Overall

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, the amounts of

Sulphur

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dioxide were at least two times as high as those of

Smoke

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over the provided period.

Similarly

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, both of them constituted the same degree in the initial year, nearly 10 units.

However

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,

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while

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apply

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the amounts of

Smoke

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increased marginally until the end of the 18th reaching the plateau at just under 500 micrograms, with a profound drop in the second half of the

17th century

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17th-century

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Sulphur

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dioxide jumped rapidly through these

years

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and by 1900 it consisted of two times more in the air than the first one. In the

years

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that followed, their figures declined dramatically

especially

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,especially

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Sulphur

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dioxides. Its level, in the next four decades, roughly halved to 500 micrograms and started to fluctuate, whilst

Smoke

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began it ten

years

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ago. These profound fluctuations continued for the next 30

years

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comprising a negative trend. Currently, their degree is as many as it used to be in the starting year.