More than half a million people have been marooned after vast swathes of land were inundated in the north-eastern Bangladeshi district of Sylhet by sudden flooding triggered by heavy rain upstream, officials said on Friday. The government opened nearly 550 temporary shelters as the flooding affected some 533,202 residents in remote villages and townships in the district, according to the local administration. “We are trying to move the flood-affected people to safety,” said Sheikh Rasel Hasan, chief administrator of the district, adding that some 4,802 villagers were shifted to the shelters in…