Patent monopoly versus open generic competition
In the US and EU a new medicine is protected by patents and regulatory exclusivity for roughly 20 years. During that window one company is the only legal seller, so it sets the price with no competitor. In India many of these molecules are off-patent or were never granted a product patent, so any qualified manufacturer may produce them. Twenty companies making the same salt must undercut each other, and the price collapses toward the cost of production.
One seller sets a price. Twenty sellers discover a price.