National Biodiesel Day is observed worldwide every March 18 to educate the public about the benefits of biodiesel and promote sustainable living. The date was chosen as it coincides with the birthday of Rudolf Diesel, the inventor of the diesel engine, who advocated for the use of vegetable oils as fuel. Biodiesel, derived from vegetable oils or animal fats through transesterification, offers several advantages over conventional petroleum diesel, including reduced greenhouse gas emissions and enhanced energy security. Celebrations may include sharing information about biodiesel, reading about Rudolf Diesel or Expedito Parente, who developed the first industrial process for biodiesel production, and using social media to promote the holiday with hashtags like #NationalBiodieselDay. It is important to note that National Biodiesel Day should not be confused with International Biodiesel Day, which is celebrated on August 10.