Heavy rain, flash flood and excessive waterflow from the upstream rivers have worsened the flood situation in many upazilas of the division.
The worst hit upazilas are Beanibazar, Golapganj and Osmaninagar in Sylhet, Kulaura, Barlekha, Juri, Rajnagar and Sadar in Moulvibazar, some upazilas of Habiganj and all upazilas of Sunamganj.
People have been suffering badly in Sylhet and Moulvibazar as the water is showing no sign of receding.
Children are also being severely affected by the floods as education institutions remained closed and waterborne diseases like diarrhoea and skin problems are spreading in an epidemic form.
A deluge of rain two days before Eid followed by overflow in the upstream Surma, Kushiara and Matijuri rivers resulted in a serious flood situation in the upazila.
Twenty villages in Sharifganj, Budhbaribazar, Bhadeswar and Bagha have already gone under water as four haors, 22 bogs and all the rivers and canals are overflowing.
The authorities have been forced to shut most of the education institutions in Mirganj because of floods.
Md Altaf Hossain, upazila nirbahi officer, said they were monitoring the situation and had asked the higher authorities for relief for the affected people.
The municipality and most of the roads have been inundated and road links with three other upazilas of Sylhet have been partially snapped.
Around 80 percent population of Dubag, Shewla, Kurarbazar, Mathiura, Tilpara, Lauta, Muria and Beanibazar municipality are affected by the flood as the Kushiara was flowing over the danger mark.
Upazila Nirbahi Officer M Asaduzzaman said the administration had already allocated 14 tonnes of relief for the affected people.
Almost all eight unions have been marooned as the Kushiara was overflowing and the dam protecting the areas has developed breaches.