The chart shows the average daily minimum and maximum levels of air pollutants in 4 cities 2000.

The chart illustrates the number of air pollutants on a daily basis among four urban areas in 2000.

Overall

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,

it is clear that

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the pollution levels considerably increased among 4 cities, and Mexico was the most polluted area,

while

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L. A encountered as the lowest number. When the amount of min SO2 oscillated in 2000, the minimum (N20), and N20 (Max) levels gradually decreased, as well, the maximum sulphur oxide followed an opposite trend, significantly increasing. In 2000, among four metropolises, the most polluted zone was Mexico, where the highest amount of nitrous oxide was almost 207, achieving the top position, compared to others, which followed by LA at 104, Calcutta (52), and 54( Beijing). In the case of minimum N20, they followed a similar direction. A different pattern can be observed in the minimum So2 levels. The largest number of sulfur sharply grew, which accounted for L. A total of only 10, compared with 59 in Calcutta

,

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and 130 in Beijing. Mexico recorded the highest maximum SO2 level at 200.

Nevertheless

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, the smallest amount of SO2

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fluctuated over

this

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period.