By not dumping rubbish in it.
The River Thames is the major river through London, cutting right through the middle of the city. There are many other rivers in London, such as the River Lee (or Lea) and the River Brent.
That would be the River Thames.
London is situated on the River Thames (pronounced 'temz'.
London is on the River Thames but not quite at its estuary.
The River Thames is found in London, England
The river Thames.
London lies on the River Thames, the longest river entirely in England. The Thames runs for approximately 215 miles, flowing through the heart of London and serving as a crucial waterway for the city's transportation and commerce.
The river Thames (pronounced temz)
The River Thames flows through the middle of London. Other rivers, such as the River Lee, flow into it within the city.
The Nile Is In Egypt and the Thames is in London
The river Thames is England, and is the river that London is built on.
The River Thames is the river that flows through London