The caste system started in India many years ago. The caste system is a Hindu tradition. People were placed into groups or levels they did not pick and they could NOT change this group or level.
It placed people into groups based on their job. Important jobs were at the top. Later, people were put into whatever group their parents were in. Nobody could change their group - ever. Caste members lived, ate, married, and worked with only people in their own group. A person was not allowed any contact with people in another caste or level.
Groups or castes when it started thousands of years ago were:
1. Priests - were at the top, along with teachers & judges
2. Warriors - they had the job of protecting and ruling the empire
3. Skilled workers, merchants, traders - were in the middle of the pyramid
4. Farmers and Servants - had a difficult life of working for others
5. Untouchables - had the worst life. They were considered low or dirty to all other groups. They were treated horrible, had zero rights, and were given the worst and dirtiest jobs.
Untouchables were given the worst jobs - like cleaning human waste (poop and urine). They were beaten by people in other groups if they "contaminated" them. Untouchables could not wear shoes or go to school. They could not touch the underground wells where others got water
In some parts of India even the sight of untouchables was thought to be dirty or unclean. The untouchables were forced to sleep during the day and work at night. Sometimes they might be given sticks to tap together to warn others they were coming.
Mother Teresa devoted her life to helping others. She moved to India at age 18 and lived there until she died at age 87. She helped many untouchables when they were sick or dying since nobody else wanted to be around them. She started special schools and hospitals for the untouchables.
Over time, the caste system changed. First, many other levels or groups were added to the caste system. It became very confusing because there were thousands of levels or caste groups. A man named Gandhi helped the untouchables get more rights. Gandhi is like the Martin Luther King, Jr. of India. He used peaceful protest to make change. The caste system was declared illegal in India but some people still believe in this old way of life.