Although the government has cited sham marriages as the reason, fears were expressed that such couples would now find it difficult to begin a life together in a state where marriage across caste groups attracts ostracisation.
According to a recent notification by the Vasundhara Raje-led BJP government, the Rs 5 lakh paid so far immediately after marriage will be cut to Rs 2.5 lakh. The remaining sum will be held as a fixed deposit in a joint account in a nationalised bank and can be claimed by the couple only after eight years - if the marriage is still on.
Also, the aid would be allowed only to couples up to 35 years of age and only if both partners are from Rajasthan.
Widows and widowers, whose spouses have not died as a result of suicide or murder and those who do not have children, will be eligible.
Social justice minister Arun Chaturvedi said the changes followed rising complaints of sham marriages in which couples tied the knot to claim the assistance and split soon after.
Officials pointed to the near eight-fold jump in the assistance paid under Savita Ben Ambedkar Inter-Caste Marriage Scheme - named after Constitution architect and Dalit icon B.R. Ambedkar's wife Savita - in the past two years.
"We have received a number of complaints regarding this (sham marriages) and decided to bring in the amendments to ensure security of marriages," Chaturvedi said.
But the government's arguments have not convinced rights activists, who said such couples would find the going tough in a society where those who marry outside their castes are often ostracised.
According the social justice department, the number of inter-caste marriages and the assistance has risen over the past few years, especially in 2013-14 when the Ashok Gehlot-led Congress government hiked the amount from Rs 50,000 to Rs 5 lakh. The total assistance paid that year was Rs 7.26 crore, up more than eight times from Rs 87.5 lakh in 2012-13.
Gehlot has accused the BJP government of diluting the scheme. "If half the amount is given after eight years, it would not be the same as giving it to a couple early on when they face difficult times. Instead of strengthening the schemes we introduced, they are posing obstacles. In rural areas, society is still caste-ridden," Gehlot said.
Others questioned the modifications too. "A couple who stand up to family, society and panchayats to lead a life together need the incentive money," Bhanwar Meghwansh, a Dalit rights activist, said.
He countered the government's contention that payments deferred until eight years would "secure" marriages and check "sham" unions.
"Why not make it 12 years then? If the government says the number of fake cases have risen after the incentive was increased, there are other ways to deal with them. File cases, recover the money and let the law takes its course. Why discourage such marriages in our fractured and caste-ridden society? Also, the government never consulted experts in the field," Meghwansh said.
Minister Chaturvedi claimed some activists had been consulted on the amendments, but did not give details.
C.L. Mimroth, head of NGO Centre for Dalit Rights, saw the change as a clear case of diluting schemes meant for the welfare of the Scheduled Castes.
"There are such cases of divorce and separation even in general-category couples. In cases involving SCs, the girl's parents often approach and bribe the police, who forcefully separate the couple and the girl is married off to someone else. In cases of such societal, police and family pressure, girls often surrender. Those who stick together need the financial backing to survive and lead the life they want," Mimroth said.