Seb, you can download some ...
Published by Vishakha Rajput, Previous COO The Water Network at AquaSPE AG
Seb, you can download some data from Indian Remote Sensing Organisation's website dedicated to Mission Clean Ganga. They have developed a website called Bhuvan where you can get data sets available for-
- Hydrological Layers ( Basin Boundary , watershed boundaries- i assume with counter maps, Drainage network )
- Water Quality at diff stations
- STP town locations
- Soil data
- Land Use Land Cover SIS-DP
- Also for major town settlement - you will get some maps.
All these data base are avialble on this site - http://bhuvan.nrsc.gov.in/bhuvan_links.php#
I hope this will help you, do you need any other specific data layer? Let us know the detail of your study project and its objectives. Best luck.