 From VOA Learning English, this is the agriculture report in special English. A small non-profit company in Cambodia is turning used cooking oil into high-quality biodiesel fuel. The idea is to reduce air pollution caused by low-quality diesel made from petroleum. In Cambodia, heavy trucks usually use petroleum diesel. So do many older cars. The diesel sold in Cambodia is a high sulfur fuel. It is banned in more developed countries. Experts say diesel exhaust is a big part of air pollution in the country. And air pollution causes lung disease and other respiratory problems. Naga biodiesel was set up in 2008 to provide a cleaner fuel choice. The company produces high-quality biodiesel at a small factory in northwest Cambodia. Most of the oil is supplied by local restaurants at no cost. The restaurants then buy back the biodiesel at a 40% discount or reduced price. The cooking oil is washed and cleaned to remove contaminants before being processed into diesel. And the process of making biodiesel has a useful by-product, glycerin, which can be used as a cleaner. The founder of Naga Biofuels says biodiesel burns cleaner in engines and helps improve the air quality in the fast-growing city of Siam Riyadh. Providing used cooking oil to biodiesel producers makes sense to restaurants, too. The manager of a restaurant in Siam Riyadh called the Blue Pumpkin says he does not have to worry about what to do with used cooking oil anymore. He adds, the whole service is very clean and professional. Naga Biofuels wants to increase production to 10,000 liters by 2013. The business plans to provide its service in environmentally sensitive areas where low-quality diesel can cause damage. For VOA Learning English, I'm Laurel Bowman.