Water and Sanitation Perspective series from Water Aid India, disseminates issues and experiences in India's water and sanitation sector. It is an outcome of WaterAid India's programme and policy work. It analyses the root causes for such a scarcity of water during the five year drought in Bundelkhand.
Here is a slightly long and complex paper but the sum and substance of it seems to be that Solar Disinfection (SODIS) combined with Nimbu pani is excellent to reduce e-coli count and inactivate it substantially. Nimbu paani also serves as an indicator that the water has been SODISED.
Attached is an interesting document from Prof. Prithvi Kandhal about using porous asphalt in parking lots so that rainwater seeps through it and recharges groundwater.
Dr. Kandhal has published many papers and has significant credentials in his areas of expertise. He resides in Jaipur after 35 years of working in the US.