>>514017289
>started to fall apart around 1900BC. By 1700BC many Indus cities had been abandoned.
The indians had to wait for the british to discover them and bring them into the modern age
>The technique of purification of drinking water by use of compressed liquefied chlorine gas was developed by a British officer in the Indian Medical Service, Vincent B. Nesfield, in 1903.
Which seems not have stuck to the indians for some reason