Crowds of flag-waving demonstrators chained the doors of polling stations shut, despite promises by protest leaders not to obstruct the polls.Advance voting has reportedly been cancelled in a number of locations.Anti-government activists want PM Yingluck Shinawatra to step down and the political system to be reformed.Protesters descended on scores of polling stations in the Thai capital, Bangkok, and several southern provinces, preventing ballot officials and voters from entering and leading to the closure of at least 34 venues.
