India's Maharashtra state has become the first in the country to ban village councils from imposing "social boycotts" that ostracise individuals or families for defying tradition.
Women and lower caste Dalits often bear the brunt of such judgments, passed as punishment for perceived misdeeds such as marrying between castes or dressing immodestly.
The western Indian state last month passed the law against a decades-old practice of village panchayats, or councils, ordering social boycotts.
"The Act was required against the backdrop of atrocities inflicted on people in the name of tradition, caste and community," said Maharashtra Chief Minister Devendra Fadnavis.
"It is necessary to prohibit social boycotts as a matter of social reform in the interest of public welfare," he said.
Under village council orders, individuals and families have been banished from the community, and denied access to temples, wells, markets and celebrations.
In some cases, panchayats have even branded women as witches, and ordered gang rapes or killings as punishment.
Maharashtra's new law declares social boycotts a crime punishable by up to seven years in prison, a fine of 500,000 (£5,200), or both.
Human rights campaigners called for other Indian states to follow Maharashtra's example.
"The law will help check caste crimes to some extent. It empowers lower-caste people and it empowers human rights organisations, as it gives us a tool with which to fight against village panchayats," said Irfan Engineer, director of the Centre for Study of Society and Secularism in Mumbai.
"We need a similar law in the rest of the country, particularly in states where (unelected) khap panchayats are strong," he added.
Khap panchayats are unelected village councils comprising men of a particular clan or caste. While their power has diminished since 1992, when elected village councils were made mandatory, they remain powerful in socially conservative states including Haryana, Punjab, Rajasthan and parts of Uttar Pradesh.
India's top court in 2011 described khap panchayats as "kangaroo courts" that are entirely illegal.
Maharashtra, home to several social reformers including B.R. Ambedkar who fought against caste discrimination, in 2013 passed legislation criminalising practices related to black magic, human sacrifices, and other superstitious beliefs.
The social boycott act is another step toward ending outdated customs, said Avinash Patil, executive president of Maharashtra Andhashraddha Nirmoolan Samiti, which had campaigned for the bill, as well as the 2013 law.
"We are demanding that the central government enact similar laws in all states, so we can end this brutal practice," he said.
