They have also been ordered to regularly inspect erosion-prone areas along rivers and canals and demolish construction works that encroach on them and remove other properties placed on protection corridors.

Some of the most threatened places are in Thanh Da in Binh Thanh District, along Ong To Canal in District 2, along the Saigon River in Cu Chi District, and near the Tan Thuan Bridge No 1 in District 4.

The People’s Committee has instructed the Department of Natural Resources and Environment to monitor and penalise people illegally mining sand in rivers and canals.

It has tasked the Department of Planning and Investment with securing priority funding for building embankments in eroded areas.

As of July there were 47 such places along rivers and canals, three more than a year earlier.

In Can Gio, the threat also comes from the sea.

Of the 47, more than half are considered especially serious, threatening the lives and properties of people living along them and the safety of waterway transport, according to the city Inland Waterway Authority.

The authority has installed warning boards at the eroded areas and worked with local authorities to persuade people to move to safer places.

The city will relocate 1,210 households living near erosion-prone areas along rivers, canals and beaches under a 2016-20 residential zoning plan, according to the People’s Committee.

They will be moved to residential areas, some built specifically to relocate people, mostly in Thu Duc, Binh Chanh, Nha Be and Can Gio districts.