buddhism caste system
Brahmanism, the predominant religion in India during the Buddha’s time, divided all humans into four castes (attu vanna), priests, warriors, traders and labourers. Social contact between each caste was minimal and the lower one’s position in the system the less opportunities, the less freedom and the less rights one had. Outside the caste system were the outcasts (sudra) people considered so impure that they hardly counted as humans. The caste system was later absorbed into Hinduism, given religious sanction and legitimacy and has continued to function right up till the present. The Buddha, himself born into the warrior caste, was a severe critic of the caste system. He ridiculed the priests claims to be superior, he criticised the theological basis of the system and he welcomed into the Sangha people of all castes, including outcasts. His most famous saying on the subject is : ” Birth does not make one a priest or an outcaste. Behaviour makes one either a priest or an outcaste”. Even during the time when Buddhism was decaying in India and Tantrayana had adopted many aspects of Hinduism, it continued to welcome all castes and some of the greatest Tantric adepts were low castes or outcastes.
Despite this, various forms of the caste system are practised in several Buddhist countries, mainly in Sri Lanka, Tibet, and Japan where butchers, leather and metal workers and janitors are sometimes regarded as being impure. However, the system in these countries has never been either as severe or as rigid as the Hindu system and fortunately it is now beginning to fade away. The exception to this is Nepal where Tantric priests form a separate caste and will neither initiate into their priesthood or allow into their temples those of other castes.

At the time of the Buddha the caste system was firmly established in India. According to this system, a person’s position in society was determined from the time he was born and there was no way to change his lot in life. There were four castes, or classes, of people in society:
(Part Two) 24. The Buddha on the Caste System
Buddha denounced the caste system and taught that a person’s actions are the measure of who a person is, whether a priest or outcast. He denounced the authority of Brahmin priests, their scripture and their rituals. He welcomed outcasts and some of the greatest tantric adepts were from the lowest caste (buddhanet.net). Unfortunately, there are Buddhists in India and Buddhist governments in nearby Sri Lanka and Nepal which still confirm and support the caste system (buddhanet.net). It is not an easy system to abolish, even with the force of law. It requires a deep change in thinking and belief.
buddhanet.net. “Dharma Data: The Caste System.” 2011. Buddhist Studies Glossary of Buddhist Terms. Web. 18 November 2011 .

The Varnashrama dharma (caste system) is the backbone of Brahminism (Hinduism), untouchability is a part of that social order. We all know that Gautama Buddha was against Varnashrama dharma, and rejected the Vedic religion. But unfortunately, we see caste system and untouchability in many ‘Buddhist’ countries. For example, the Burakumin/Eta in Japan, Baekjeong in Korea, Ragyabpa in Tibet, etc. As we know as Buddhists that the Buddha was no hindu, then why this system is also in the societies of Buddhist countries?
However, what is special in Hinduism is that the caste system is found in the religious scriptures and is part of the religion. A religion-enforced caste system is not found in Buddhism. Buddhism also does not comment on the political ideology of lay societies e.g. democracy, capitalism, monarchy, socialism, communism etc.

Portrait of a young B.R. Ambedkar, architect of the Indian Constitution and founding father of modern India. Image courtesy of Creative Commons
Though the Buddhists remain optimistic that this will happen, some are skeptical. It is legitimate in India for the government to remove temples and shrines, even Hindu ones, for infrastructure projects, and, according to Giresh Gupta, an author and guide living in Ahmedabad, the replacement will never come.
References:
http://www.buddhanet.net/e-learning/buddhism/lifebuddha/2_24lbud.htm
http://grademiners.com/free-papers/history/caste-system-in-india-hinduism-and-buddhism
http://buddhism.stackexchange.com/questions/28291/what-is-the-opinion-of-buddhism-on-the-caste-system-and-untouchability-of-hindui
http://religionnews.com/2017/05/11/a-dalit-community-looks-to-escape-the-caste-system-by-converting-to-buddhism/
http://www.buddhanet.net/e-learning/buddhism/lifebuddha/2_24lbud.htm