The sudden change in the colour of the water of Boga Lake in Bandarban, one of Bangladesh's most popular tourist destinations, has sparked wide discussion.

Pictures shared on social media show the lake's water has turned murky, though tourists know it for its blue water. Local journalists say that since the news spread, more tourists have been coming to see the changed lake.

The change has led to much discussion on social media, and various myths have spread among the local hill communities.

However, Bandarban journalist Monu Islam, citing local people, says the lake's water turns murky of its own accord every year at this time, in winter around January. "Every 3-4 years the water gets so murky it turns almost yellow. That is what has happened this time too."

He said the murkiness lasts about a month, after which the water slowly turns grey and then clear blue again.

Mr Islam said locals believe that in a year when the water is murkier, jhum cultivation yields more.

Md Alamgir Ruma, a resident of the Ruma area and a tourist guide, says the water of Boga Lake turns murky at this time every year and that it lasts 15-20 days. He said the water began turning murky about a week ago this year.

Source: BBC Bangla. First published in Bengali on The Agro News.