In the history of India and Hinduism what group of people did not belong to the caste system and were not protected by caste law?

In the history of India and Hinduism, the group of people often referred to as "Dalits" or "Untouchables" did not belong to the Caste System and were not protected by caste law. They were historically marginalized and subjected to severe discrimination, facing social exclusion and restrictions on their rights. This group was considered outside the traditional four-tier caste structure, which included Brahmins, Kshatriyas, Vaishyas, and Shudras. Dalits have long fought for social justice and equality, especially in the modern era.