There are several factors that contribute to the limited amount of information we have about ancient India:
1. Lack of written records: Although ancient India had a sophisticated system of writing, much of the knowledge and history was transmitted orally, which means that it was passed down from generation to generation, and could have been prone to distortions and additions over time.
2. Environment: Ancient Indian texts were often written on perishable materials such as palm leaves and animal skins, which were vulnerable to damage from moisture and insects.
3. Natural disasters: Ancient India suffered from occasional natural disasters such as floods and earthquakes, which destroyed many ancient monuments and artifacts.
4. Foreign invasions: Over the centuries, India was invaded by several foreign powers such as the Indo-Greeks, Indo-Scythians, Kushans, and Muslims, who destroyed many ancient monuments and works of art.
5. Colonialism: The British colonial government had limited interest in Indian history and culture, and the preservation of ancient India was not a priority for them.
Despite these challenges, archaeologists and historians have made significant progress in uncovering the rich history and culture of ancient India, and new discoveries are being made all the time.