Clashes broke out between BJP supporters and student activists and those of the Left and Trinamool Congress Chatra Parishad (TMCP) during Amit Shah's roadshow in the city on Tuesday, officials said.
Trouble began after stones were pelted at Amit Shah's convoy as it passed through College Street and the arterial Bidhan Sarani on its way to Swami Vivekananda's residence in north Kolkata, a little over 3.5 km from Esplanade in the heart of the city, where it began.
A scuffle broke outside the Calcutta University campus on College Street, when student activists of both the Left and the TMCP shouted slogans against Shah, they said.
They showed black flags and waved posters with "Amit Shah go back" written on them.
The police controlled the scuffle.
A clash took place outside Vidyasagar college and university hostel when TMCP activists threw stones at Shah's convoy, the officials said.
The agitated BJP supporters locked the gates of the hostel and set cycles and motorbikes parked outside on fire.
They also threw stones at the building.
A bust of Ishwar Chandra Vidysagar, after whom the college is named, which was outside hostel building was broken by BJP supporters during the clash, the officials said.
A huge police contingent was rushed to the spot and controlled the situation, they added.
English questioning rose from 20 per cent to 31 per cent, and racist jokes from 36 per cent to 41 per cent
Workplace violence against Black and ethnic minority employees rises to 26 per cent
Highlights
The Trades Union Congress surveyed 1,044 Black, Asian and ethnic minority employees. The results show clear increases in racist behaviour between 2020 and 2026.
Workers having their English questioned rose from 20 per cent to 31 per cent. Those hearing racist jokes went up from 36 per cent to 41 per cent.
Racist comments made to workers or around them increased from 31 per cent to 36 per cent.
Violence and threats
The most worrying finding involves physical threats and violence, which jumped from 19 per cent to 26 per cent.
Racist posts shared on workplace social media grew from 22 per cent to 28 per cent. Racist materials being passed around increased from 19 per cent to 25 per cent.
Beyond direct racism, many workers face unfair treatment. Nearly half (45 per cent) said they get harder or less popular jobs.
Over two in five (43 per cent) receive unfair criticism. The same number (41 per cent) stay stuck on temporary contracts.
Work conditions got worse too. Those not getting enough hours rose from 30 per cent to 40 per cent.
Workers denied overtime went from 30 per cent to 37 per cent. Being kept on short-term contracts increased from 33 per cent to 41 per cent.
Direct managers cause most unfair treatment (35 per cent), followed by other managers (19 per cent).
Bullying mainly comes from direct managers (30 per cent) and colleagues (28 per cent). Racist behaviour mostly comes from colleagues (33 per cent) and customers or clients (22 per cent).
Paul Nowak, TUC general secretary, said: "Black and ethnic minority workers are facing appalling and growing levels of racism and unfair treatment in Britain. This racism is plaguing the labour market – and it's getting worse."
The TUC is calling for urgent government action to tackle the problem. The union wants ring-fenced funding for the Equality and Human Rights Commission to enforce workplace protections.
It is pushing for mandatory ethnicity pay gap reporting for companies with over 50 employees.
The TUC says the Employment Rights Act, which makes employers responsible for protecting workers from harassment by customers and clients, will be an important step forward.
The union also wants employers to treat racial harassment as a health and safety issue and monitor ethnicity data across recruitment, pay and promotions.