Millions of people in more than 800 cities in 30 countries are participating in a car-free day today, according to Margot Wallstroem, environment commissioner for the European Union. The day — marked throughout Europe and in other spots from Buenos Aires to Tel Aviv — is aimed at raising awareness about pollution and traffic congestion, particularly as high gasoline prices have people’s attention. Participating in the first car-free day in Bangkok, Thai Prime Minister Chuan Leekpai and several of the country’s cabinet ministers walked, biked, or took public transit to work today. Chuan said that if the car-free day proved popular, it might be extended to weekends on a trial basis. Still, this latest car-free campaign hasn’t made as much of a splash in Europe as intended.