The original gridded global PM2.5 files are available @ http://fizz.phys.dal.ca/~atmos/martin/?page_id=140
Individual gridded, state, and district level maps for years 1998 to 2014 for India are available here
The state and district boundary shapefiles used for this analysis are from 2011 Census, and are available at Github
PM2.5 trends for Indian states from 1998-2015- view
PM2.5 trends across districts from 1998-2015- view
The Indo-Gangetic Plain is the most polluted while parts of Leh/Ladakh, and Arunachal Pradesh are the cleanest.
Please send your comments, questions, and data requests to firstname.lastname@example.org