Since 25 August, over 620,000 Rohingya refugees have crossed the border from Myanmar into Bangladesh. Their arrival comes on top of hundreds of thousands of other Rohingya who arrived in previous years and were already living in difficult conditions. MSF has significantly scaled up its medical, water and sanitation efforts in support of the growing population. The makeshift settlements are densely populated and living conditions remain precarious. If the situation doesn’t improve, there is the potential of a public health emergency.