Hindus also participate in the cattle product industry, but further along in the supply chain. Jaweed Iqbal Quraishi, the owner of a business in the city of Malegaon that used to crush cattle bones and sell them to gelatin manufacturing companies, claimed that all his customers were Hindus. “They are calling me every day and asking why such a rash action was taken by the government,” Mr. Quraishi said.

If that is true, it is not something many people are comfortable discussing in India today. Of the three customers mentioned by Mr. Quraishi, two declined to comment, and Deepak Kapadia, a procurement executive at India Gelatine & Chemicals, denied that his company had ever bought cattle bones from Mr. Quraishi or anyone else.

The Rise of Buffalo

There have been bans on beef in other Indian states for decades — the Maharashtra ban was the 11th — but there is no body of research on the economic effects. One result could be more buffalo slaughter. Exports of buffalo, which are not revered, rose 16 percent during B.J.P.’s first six months in office, compared with the same period a year earlier. According to India’s most recent livestock census, buffalo make up just over a third of the national bovine inventory, yet their proportions are significantly higher in states like Haryana and Punjab where beef bans have been in place since shortly after independence in 1947. States that do not prohibit cattle slaughter, such as Kerala and West Bengal, have almost no buffalo.

At Deonar, the number of buffalo being slaughtered is rising: about 300 a day, up from 90 before the ban. Indian buffalo meat is already prized in the Arab and East Asian markets. Last year, India exported $4.3 billion of beef, ostensibly all from buffalo, because India has never allowed the export of cattle meat, even before the recent law was passed. Still, a Mumbai exporter of buffalo meat with 25 years of experience said that it was well known in the industry that cattle meat regularly made its way into exports.