MUMBAI, India — When 2-year-old Rutuja playfully tipped over a bottle, spilling water onto the mud floor of the family’s shack, her mother, Nageshwari Rathore, let loose a screech, lunging forward as though to slap the toddler. Ms. Rathore stopped herself, sinking her head into her hands. “You finished it,” she whispered.

The loss wrenched at the 25-year-old. That June morning she had stood in line in the scorching heat for over an hour to collect five liters of water. A government tanker rolls up once a day to the abandoned field where she now lives.

Located in Ghatkopar, a Mumbai suburb, the field functions as a relief camp for 350 families who have left their villages in rural Maharashtra because of a drought, the worst in 100 years. Wild pigs root through the open sewer that runs alongside the Rathores’ tarpaulin shack. When the monsoon arrives, possibly in the next few days, it will flood the camp and force the family out.

Over 330 million Indians — about one quarter of the country’s population — have been affected by the drought. In this western state, where over half the population is dependent on the rural economy, the effects are severe. An average of nearly nine farmers committed suicide every day last year, primarily over debt related to crop failure.