 Shops in the Thai capital have begun imposing emergency rationing as the Prime Minister warned parts of Bangkok could be flooded for up to a month and authorities called a  five-day holiday to give people the chance to flee.  an evacuation warning to residents of a riverside district some way from swamped northern parts of the city deepened anxiety, as residents scrambled to stock up on food and water.  after assessing the situation, we expect floodwater to remain in Bangkok for around two weeks to one month before going into the sea,  said Prime Minister Yingluck Shinawatra.  However, we shouldn t face water as high as two or three metres staying for two or three months as we ve seen in other provinces.  Thailand s worst flooding in half-a-century has killed at least 366 people since mid-July and disrupted the lives of nearly 2.5 million, with more than 113,000 in shelters and 720,000 people seeking medical attention.  With a high tide approaching in the Gulf of Thailand, climate change experts said the city s fate rested with river dykes holding.  In the worst-case scenario, if all the dykes break, all parts of Bangkok would be more or less flooded,  said Seri Supharatid of Rangsit University s Centre on Climate Change and Disaster.  The economic damage is difficult to quantify, but the central bank has revised its growth forecast for southeast asia s second-biggest economy to 3.1% from 4.1% earlier this month.  Flooding has forced the closure of seven industrial estates in ayutthaya, Non-thaburi and Pathum Thani provinces bordering Bangkok, disrupting supply chains and putting 650,000 people temporarily out of work.  The floods are expected to take a toll on the  tourism industry, which employs more than two million and accounts for 6% of gross domestic product. Tourism Minister Chumphol Silpa-archa said arrivals could be 500,000 to one million below the Government s target of 19 million this year.