One of the main reason is its price. Dishwasher is a costly appliance which many people can't afford or doesn't want to spend for washing utensils only.
Another reason a dishwasher is not so popular enough in India is due to its automated mechanism. Here, many people believe that the friction that human hands, soap, and a scrubber can create, a dishwasher can’t replicate that.
Hence, in India still, the use of dishwashers is not so widespread yet.