Complex sentence: By 2014, a majority of countries had discontinued the use of leaded gasoline for automobiles, yet leaded gasoline continues to be produced and used; for example for private aviation in the United States.
Split into simpler sentences: By 2014, a majority of countries had discontinued the use of leaded gasoline in automobiles. Yet leaded gasoline continues to be produced and used, for example, for private aviation in the United States.