The Biofuels International website reports that although their research/analysis points to the use of aviation biofuel blends as the only way to reduce aviation-related GHG emissions, the recent grounding of flights in Europe, due to volcanic ash fallout from Iceland's Eyjafjallajoekull volcano, may have opened "other possibilities". "On a normal day, the 28,000 flights in European airspace emit about 560,000 tonnes of carbon dioxide, or a third of the world's aviation emissions". The grounding of some 63,000 flights in Europe for four days due to the volcanic eruption in Iceland, has reportedly saved "1.3 million tonnes of carbon dioxide, more than the annual emissions of many developing countries"..