Austin retailers and grocery stores could no longer offer plastic bags at checkout counters under a ban Mayor Lee Leffingwell and two other City Council members will propose today . The ban would be phased in gradually, though it's not clear when it would start. Leffingwell said Sunday that plastic bags pollute waterways, harm wildlife, clog drainage systems and take up landfill space, where they don't biodegrade. A January report from the city's Solid Waste Services Department said Austinites use 263 million plastic bags a year, and the bags cost the city $850,000 a year to put in landfills and...