Fuel contamination occurs when unwanted substances mix with fuel, making it less effective or even harmful. Common contaminants include water, dirt, and bacteria, which can enter fuel tanks through leaks, condensation, or poor storage practices. This contamination can lead to engine problems, reduced performance, and increased maintenance costs. To prevent fuel contamination, it's essential to store fuel properly and regularly check for signs of impurities. Using clean containers and ensuring that fuel tanks are sealed can help keep contaminants out. Regular maintenance of vehicles and equipment also plays a crucial role in identifying and addressing any fuel quality issues early on.