Wikipedia defines ‘travel’ to be “the movement of people between distant geographical locations. Travel can be done by foot, bicycle, automobile, train, boat, bus, airplane, ship or other means, with or without luggage, and can be one way or round trip.”
Meanwhile, it defines ‘tourism’ as “travel for pleasure or business; also the theory and practice of touring, the business of attracting, accommodating, and entertaining tourists, and the business of operating tours.”
Tourism, essentially, comes under the broad framework of travel. While travel can be undertaken for pleasure or entertainment, tourism is purely business and is a main source of revenue, especially in India.