The Vedas are the most ancient holy scriptures of the Hindu religion. These are a series of poems describing the lives of the Hindu gods and heros, and show a sophisticated urban world like that of the Harappan Indus Valley culture. The Vedas were based on a complex star calendar, which dates them to at least 2400 BC. They were composed in an ancient Indo-European language called Sanskrit.

It now appears almost certain that the people who wrote the Vedas were the same as those of the Harappan culture, an ethnically mixed group of people. The population of the area today, Gujaratis and Punjabis, are said by anthropologists to be ethnically the same as the population of Harappa 4000 years ago. Linguistically the present day population of Gujrat and Punjab belongs to the Indo-Aryan language speaking group, so the ancient Harappans could be the mother culture of all the Indo-Europeans.

Severe climatic changes hit north India. The Sarawasti river dries up, probably due to climatic or geological changes (for example earthquakes). This also marked an end of the city of Mohenjodaro. (The Sarawasti river was, known from the Vedas, is not found until satellite photos show the dry river bed in 1990s. Until then many people thought the stories about the great river were just made up.) Around 1500 BC another great city disappeared, this time due to flooding. This was Dwarka a major port city in what is now Gujarat, which was submerged by rising sea levels. Iron was in use in north India by this time. All these diasters may have caused waves of people to leave India for central and west Asia.