Trees and grass are being planted along both banks, and a floating garden made up of five islands will be added to the river.

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Next we turn north, floating past the fragrant botanical garden of Lord Kitchener's Island and the domed tomb of the Aga Khan, high on a sandbank to our left.

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Occasionally we are immensely cheered by, say, the humiliation of Member of Parliament obliged to admit that he had asked the state to pay for a floating duck island in his garden.

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