SANAA, Yemen (AP) — In Yemen's third largest city, residents are battling back against a months-long siege by Shiite rebels, armed by airdrops of weapons by planes from the Saudi-led coalition, with hundreds killed and food, water and medicines running short in a potentially pivotal battle in the country's protracted civil war. Taiz is considered Yemen's cultural capital, with one of the country's main universities and a relatively cosmopolitan, politically minded population — it was a major center, for example, in the 2011 pro-democracy uprising that eventually led to the removal of longtime autocrat Ali Abdullah Saleh. [...] Houthi rebels hold the university, located on elevated ground on the western outskirts, and rockets and tank fire from there hammer residential neighborhoods. The U.N.