A rather uncommon thing in India. So, unless you want to switch to the Indian water-bucket-hand system, you should carry around a role of paper. The prices for toilet paper are ridiculous. You pay something like 0.8€ per role (and they are not bigger than somewhere else). It's available in single roles in the small Shop in H12 or in bigger packs at DMart and Heiko.
As these facilities are not always open, you should bring at least one role to start with when you arrive!