Is there any polygon shapefile of slums in New Delhi? This paper (Emissions inventory of anthropogenic PM2.5 and PM10 in Delhi duringCommonwealth Games 2010) showed a map of the slums but I can't find the source of their data.
I found this website (https://resourcewatch.org/data/explore/cit049-Urban-Land-Use-India_1?section=Discover&selectedCollection=&zoom=3&lat=0&lng=0&pitch=0&bearing=0&basemap=dark&labels=light&layers=%255B%257B%2522dataset%2522%253A%2522e354f7b8-0fca-422f-bf12-fc6189812bec%2522%252C%2522opacity%2522%253A1%252C%2522layer%2522%253A%25228efadc4d-7663-4666-ae69-fdf2dccd0cbd%2522%257D%255D&aoi=&page=1&sort=most-viewed&sortDirection=-1) where they provide Land Use data for the years 2016 and 2019 for whole India in raster format (10m spatial resolution).