In 1947, the British departed with 24/7 pressurized water across the developed parts of India.
Now, the British-built water system has all but collapsed. Instead of pressurized water, the water comes weakly and only intermittantly. What difference does that make, you ask?
Well, if a pressurized system leaks, the leak causes water to leave the pipe. In a non-pressurized system--coupled with the user-side pumps that are used to pull in more water--leaks flow INTO the water line, bringing contamination with it. Couple that with the common practice of placing fresh water and sewer lines in the same trench and everytime somebody pumps that water toward them, they are pulling in fecal matter that leaked from the adjacent sewer lines, which also leak.
That's why Indians often cannot drink their water without going through reverse osmosis. This is just an example of how India frittered away a resource the British brought them.