In what time period did the Indian class system begin to change?

Indian class system begin to change in the 1500 BC

Explanation:

The Indian class system began with the incoming of the Aryans in the 1500 BC to India who had come from south Europe and north Asia. The class system in the Indian society comprised of the Brahmins, Kshatriyas, vaishyas which were impacted by the Indo European societies.

Shudras were addition to the society by the Brahmans only. But a law was passed in the year 1950 to abolish this discrimination system in the society. But the practice of untouchability still continues to be a part of the society even today.