Spoken Hindi
Hindi is the widely spoken in India. More than half of Indian’s have got Hindi as their mother tongue and so Hindi is the most major spoken language in India.
Hindi has the largest base of speakers in India compared to any other languages .If you don't know the local language, Hindi is manageable.
The whole of India outside your home state will seem like your Home and you will not feel like an outsider. When a Gujarati or a Punjabi or a Bengali you meet and interact with cannot speak your mother tongue, and is also not good at speaking in English, you can use Hindi for communication.