Outside the capital, people have demonstrated at more than 150 places. There's no let up in the momentum as the local government struggles to resolve the crisis: more than a million people are estimated to have protested across Tamil Nadu on Friday. Public transport has been affected; schools, colleges and businesses are shut. Oscar-winning music composer and Tamil Nadu's most well-known celebrity, AR Rahman, has tweeted that he's fasting in support. Cricket and movie stars have backed the movement. An overexcited newspaper report has even called it India's Arab Spring.
That may well be an exaggeration. But there is little doubt, as a journalist who is covering the protest says, that what began as small protests against the arrest of 200 young men opposing the ban last week has now snowballed into a "mass movement, leaderless and largely peaceful".
Animal rights activists, who support the ban, say the sport is cruel to animals. Nonsense, say the bull owners and supporters: the sport is a 2,000-year-old tradition and a way of life with people in large swathes of Tamil Nadu. They say the animals are, by and large, well looked after.
Opinions diverge greatly on the subject. Federal minister Maneka Gandhi has called the festival a day of "violence and killing" where "boys jump on each one (bulls) and try to tear its horns off". She wrote: "Everyone in India looks down upon it - as civilised people should."
Her comments have attracted a lot of flak. Shyam Krishnakumar, a research associate with Vision India Foundation, says: "This statement typifies a cosmopolitan elitism that considers itself to be modern and progressive and rural India to be backward and barbaric, in need of being saved. There is little effort taken to understand and sincerely engage with their lives and worldviews, there is merely the civilising mission to be force-fed to everyone, for their own good of course."
'Bull by the horns'
Activists and bull owners have fought in the courts over the fate of the sport for more than a decade. In 2014, the Supreme Court banned it - and last year upheld the ban after a fresh challenge.
But the January protests - "taking the bull by the horns", as my favourite headline says - is unrivalled in recent memory.
They have been spontaneous and not led by any political party. They have cut across Tamil Nadu's often fractious caste and class lines. Participants include students, info-tech professionals, factory workers, farmers, anti-nuclear activists, and many other ordinary folk.
And the protests are no longer just about bulls. There are people angry with the recent currency ban and the shortage of cash and the controversial judicial order making it compulsory to play the national anthem in theatres and for audiences to stand when it is being played. There are people who have protested against a nuclear plant in the state and against GM crops. There are irate drought-hit farmers who feel they are being deprived of their share of water from a river that their state shares with neighbouring Karnataka.
They share, say many, deeper anxieties about what they feel are assaults on local traditions and cultures by the federal government, judiciary and elites in Delhi. Many of them say they are resisting attempts at "homogenising" India by federal fiats. The protests, many say, represent an inchoate movement, almost like a harbinger of things to come.
"Jallikattu is just a trigger. This huge protest is a manifestation of the trust deficit between Tamil people and the federal government and the judiciary," says historian AR Venkatachalapathy. "They even distrust the media in Delhi which portrays Tamils as some exotic people with weird customs. Many don't trust Prime Minister Narendra Modi's BJP government's muscular nationalism and recent moves like the currency ban."
Like most uprisings, this is also likely to fizzle out as the authorities try to placate the protesters by bringing in temporary laws to allow the festival this year. But the protests mirror modern-day fears about globalisation and anxieties about loss of identity, living, and culture - and authorities who don't care.