Central to Jain beliefs is the doctrine of ahimsa, meaning nonviolence or non-injury, and the practice of vegetarianism.
Jains are forbidden to have any occupation that involves the destruction of living beings. They may not eat meat or eggs, and farming is taboo because in the process of plowing, weeding and harvesting living creatures are destroyed. Even pulling up root plants, such as potatoes or onions, is destructive. Also prohibited are jobs that involve using fire or poisonous materials, or trades that have to do with slavery or animal husbandry. Hence, most Jains are in the merchant class.
Observant Jains don’t go out or eat at night or when it is dark, so as to avoid accidentally consuming or stepping on a living creature that they don't see. They carry a whisk to brush aside insects from their path, and wear a cloth over their nose and mouth to prevent inhaling living creatures. During the rainy season in India, monks stay in one place, mostly indoors, so as to avoid stepping on the myriad living creatures that inhabit the surface of the soil during wet periods.
The doctrine of nonviolence leads Jains to be vegetarian. In fact, widespread vegetarianism in India is the result of Jain teachings and influence – not Hindu or Buddhist particularly.
Hindu spiritual leader Mahatma Gandhi is mostly responsible for making ahimsa well known as a concept, in the political form of passive nonviolent resistance. He formulated his ideas of truth and non-violence in his early years through his involvement with a Jain sect. This is probably the most globally visible contribution of Jainism to the world.