The line graph presents data on pollution levels in London from 1600 to 2000, focusing on two main contributors: smoke and sulphur dioxide.
In 1600, the pollution levels attributed to smoke and sulphur dioxide were approximately 50 and 52 micrograms per cubic metre, respectively. Between 1650 and 1700, the pollution level caused by smoke steadily increased to 200 micrograms per cubic metre, while the level of sulphur dioxide pollution dramatically rose to 700 micrograms per cubic metre. An erratic decrease in pollution levels caused by both smoke and sulphur dioxide was observed in 1750.
From 1800 to 1900, pollution levels due to smoke and sulphur dioxide experienced a significant increase, reaching nearly 450 and 900 micrograms per cubic metre, respectively. Finally, from 1900 to 2000, there was an erratic decrease in both factors of pollution levels, gradually approaching zero.
In summary, by 2000, pollution levels in London due to smoke and sulphur dioxide had significantly decreased, nearly reaching zero.