The pie charts provide data regarding the trend changes in the main causes of pollution in a specific area of an ocean in two distinct years: 1997 and 2007.
Overall, pollutants from air, litter, farm waste, industrial waste, and marine pollutants decreased over the given period, whereas pollution caused by offshore oil and domestic sewage increased. Notably, litter contamination was totally eliminated by 2007.
To begin with, air pollution decreased by just 1%, from 30 percent to 29 percent. Conversely, waste from farms and industries almost halved, falling to 2% and 9%, respectively. Marine contamination dropped slightly by 5%, from just under a quarter to nearly one-fifth.
In contrast, domestic sewage pollution witnessed a dramatic growth of 60%, from 18 percent in 1997 to 29 percent in 2007, becoming the largest contributor to oceanic pollution. Similarly, offshore oil almost tripled from 5 percent to 14 percent between 1997 and 2007.