Vehicle fuel (gasoline and diesel) sold by six Korean oil refiners, SK Energy, Hyundai Oilbank, S-Oil, GS Caltex, Nonghyup and Korea National Oil Corporation (supplier of discount gas station) in the metropolitan area during the second half of 2016 boasted world-class environmental friendliness.

Metropolitan Air Quality Management Office (Administrator Kim Sanghoon) announced that the evaluation on the quality of vehicle fuel sold in the metropolitan area during the second half of 2016 showed that both gasoline and diesel of SK Energy, Hyundai Oilbank, S-Oil, GS Caltex, Nonghyup and Korea National Oil Corporation (KNOC) were all rated five stars in the environmental quality rating.
In terms of gasoline, all of the six oil companies received the five-star grade in two items, benzene content and sulfur content, out of six criteria and five refiners except KNOC were given five stars for aromatic compounds and 90 percent distillation temperature.

All six refiners received relatively low ratings with two or three stars for olefin content and steam pressure. For diesel fuel, they all received five stars in five categories including sulfur content and cetane number.

In case of aromatic compounds, S-oil was rated with four stars while the other five companies received three stars.
Under the Special Act on the Improvement of Air and Environment for Seoul Metropolitan Area, the evaluation on environmental quality of vehicle fuel has been conducted since 2006 to induce consumers to purchase eco-friendly fuel and encourage fuel manufacturers and supplies to improve environmental quality of their products.

The evaluation is conducted twice a year by collecting 45 samples of gasoline and diesel fuel from oil storages and gas stations in the metropolitan area to grade the environmental quality.

By analyzing the six respective items including aromatic compounds for gasoline and diesel, the evaluation is graded in five classes from five stars to one star, which helps enhance the environmental quality of vehicle fuel.

Under the Government 3.0 policy which pursues openness, sharing, communication and collaboration, the Metropolitan Air Quality Management Office has been announcing the result of evaluation on environmental quality rating of fuel twice a year.