Dear Purnima,
Every state, whenever it is affected by drought, estimates the damage/loss and sends a memorandum of loss to the Ministry of Home Affairs, for financial assistance. These documents are not secretive, but they are not in public domain (usually). Some states have them in public domain. As of now, MHA does not have these documents online. By contacting the respective states, one can access this data. I can also say that there is no official compilation of this data at national level.
Best,
ArchiPlanner