The chart below shows the average daily minimum and maximum levels of two air pollutants in four big cities in 2000. Summarise the information by selecting and reporting the main features and making comparisons where relevant

The column graph delineates the highest and lowest contaminant

rate

caused by two ingredients (SO2 and N2O) in four urban areas, namely LA,

Calcutta

, Beijing, and Mexico in the year 2000. Looking from an

overall

perspective, it is obvious that the

rate

of air pollution caused by SO2 and N2O was remarkably higher than in the other three cities,

while

the lowest

rate

of that was in Los Angeles in the period shown. As is presented in the graph, the minimum SO2 and N2O which was emitted into the atmosphere were 80 and 113

micrograms

per m3, respectively, in Mexico, and the highest figures for SO2 and N2O emitted were 200 and 207

micrograms

in turn. Meanwhile, in Los Angeles, the level of pollutants caused by SO2 varied from 1 to 10

micrograms

per m3, and as for the records of N2O, the lowest

rate

caused air pollutants in LA was 39 micro-grams, the highest

rate

was almost ten times higher than the figures for SO2.

In contrast

to LA and Mexico, the level of SO2 which caused polluted the atmosphere was larger than the figure for N2O. With regard to SO2 emission, the level of that in

Calcutta

was 47 micro-grams, nearly double in comparison to Beijing. The highest of

micrograms

of SO2 in

Calcutta

, in opposition, was halved lower than in Beijing. Turning to the

rate

of N2O emission, the figure for minimum emission was 30 and 14, respectively, in

Calcutta

and Beijing. Meanwhile, the maximum air pollution in the two big cities was equal in the amount of N2O.