Pneumatic elevators are certainly used in the United States, especially, I believe, in tall buildings. If you go to an Embassy Suites hotel, you can see them in action where a single large cylinder extends below the elevator cab, pushing it up.
This is at the edge of my expertise. But, as a quality manager aware of safety issues, I would say that the big concern would be: Would India find it affordable to install and maintain pneumatic elevators that would run reliably. The difference between using pneumatics for machine equipment and for elevators for people is that each failure of an elevator for people creates a lot of inconvenience and some risk (falling is very unlikely, but being stuck for hours is a real possibility, and, if people have health problems, that is risky. The high reliability required, of course, increases cost. Regular maintenance and routine excellence in quality (ISO 9000 is a good set of standards for this) are essential.
To research this, I would look to see if there are any ISO 9000 certified elevator companies or pneumatic companies in India, and see if they are up to the task.
As for long conveyor belts and large shipments, I've never heard that pneumatics offers efficienty on these over electricity.
Two other possibilities: Perhaps India could quickly supplement electrical power with inexpensive solar. Also, a method was developed in the seventies in village India that generated enough electricity for four hours a day for each village using the cow manure, producing methane, and generating electricity. The same process also increased the quality of fertilizer.