The graph below shows the level of the ozone (microgram) in four different years during a particular day from 0 to 21 o'clock. Summarize the information by selecting and reporting the main features, and make comparisons where relevant.

The line chart illustrates the changes in ozone ( microgram ) levels, measured in micrograms, in a day, from 0 to 21 o’clock, in four distinct years. Overall, ozone levels were generally highest in 2012 and lowest in 1992 throughout most of the day. Additionally, while most years experienced relatively stable fluctuations, the year 1992 […]