Brazil's oil regulator ANP temporarily decreased the mandatory mix of ethanol and biodiesel in fuels in Rio Grande do Sul state for 30 days, starting on 3 May, amid floods in the region.
The anhydrous ethanol blend on gasoline was lowered to 21pc from the current 27pc, while the mandatory biodiesel mix for 10ppm (S10) diesel is now at 2pc, down from the usual 14pc.
The agency also temporarily suspended the blending mandate for diesel with 500ppm of sulfur (S500).
ANP said it can revise deadlines depending on supply conditions in the state.
Rainfall in Rio Grande do Sul blocked railways and highways where biofuels are transported to retail hubs, such as Esteio and Canoas.
Supply of fossil fuels via pipeline from the 201,000 b/d Alberto Pasqualini refinery (Refap), in Canoas, and other retail bases has not been compromised, ANP said.
Floods in Rio Grande do Sul have left at least 83 dead and 111 missing, according to the state government. More than 23,000 people have been forced from of their homes amid widespread damage. Over 330 cities are in a situation of public calamity.