Maine residents who buy low-polluting, high-mileage cars would be eligible for rebates of up to $3,000 under a bill that will go before the state legislature in January. And under a separate new program in the state, cars that meet particular green criteria will be marked at dealerships with stickers that read “Cleaner Cars for Maine,” an effort to help prospective car buyers take the environment into account in their purchasing decisions. In other clean car news, Vietnam announced this week that it plans to phase out the use of leaded gasoline, the only type of fuel now in use in vehicles in the nation.