Is $10 a day really possible?

Yes, but it is not a vacation. It is a survival-based travel style that involves constant vigilance and zero luxury.

You must keep an emergency buffer fund of at least $300 accessible in a separate account for clinic visits or medicine.

India on $10 a Day: The Long-Term Backpacker's Manual

To survive on $10 a day in India, you must live exclusively in shared hostel dorms or railway station waiting rooms, eat only street food like dal and roti, and travel exclusively by unreserved 2nd class sleeper trains. This lifestyle requires strict discipline, avoiding all alcohol, cafes, and tourist-targeted attractions that charge entry fees.

Master the Indian Railways. Book 'General' or 'Sleeper' class tickets as far in advance as possible. Never use AC classes. Use the official IRCTC website or the 'Where is my Train' app to track unreserved coaches to avoid being stranded.
Eat strictly street-side. Look for 'Dhabas' where locals eat. A full meal of dal, seasonal vegetable subzi, and rotis should cost between 40-70 rupees ($0.50-$0.85). Avoid restaurants with printed menus or English signage.
Sleep in basic dorms. Target hostels that charge under 300 rupees ($3.60) per night. Use sites like Hostelworld, but call ahead to negotiate a 'long-stay' rate if you plan to stay in one city for more than a week.
Eliminate 'Hidden' costs. Drink only filtered water from community refill stations (usually 1-2 rupees per liter) or carry a life-straw bottle. Never buy bottled water. Walk everywhere instead of taking rickshaws.

Is $10 a day really possible?: Yes, but it is not a vacation. It is a survival-based travel style that involves constant vigilance and zero luxury.
What if I get sick?: You must keep an emergency buffer fund of at least $300 accessible in a separate account for clinic visits or medicine.