Hospitals and clinics across India turned away patients except for emergency cases on Saturday as medical professionals staged a 24-hour shutdown in protest over the rape and murder of a doctor this month in the eastern city of Kolkata.

More than one million doctors were expected to join the strike, paralysing medical services across the world’s most populous nation. Hospitals said faculty staff from medical colleges had been pressed into service for emergency cases.

The walk-out was the latest action in response to the killing of a 31-year old trainee doctor last week inside the medical college in Kolkata where she worked.

The crime has triggered nationwide protests among medical workers and a public outpouring of anger over violence against women reminiscent of what followed the notorious gang rape and murder of a 23-year-old student on a bus in New Delhi in 2012.

The strike halted access to elective medical procedures and out-patient consultations, according to the Indian Medical Association (IMA).

There was a heavy police presence outside Kolkata’s RG Kar Medical College where the woman was killed, while the hospital premises were deserted, according to the ANI news agency.

Mamata Banerjee, the chief minister of West Bengal, which includes Kolkata, has backed the protests across the state. Her government announced on Saturday evening measures to improve security for women working night shifts, including designated rest rooms and safe zones monitored by cameras.

It also asked private institutions to consider measures such as night patrols to make the working environment more secure for women.

India’s Central Bureau of Investigation has so far detained one suspect in the case.

The CBI summoned a number of medical students from the college as part of its investigation, according to a police source in Kolkata, who said the agency also questioned the principal of the hospital on Friday.

There were protests throughout the day in Kolkata, led by doctors, civil society members and political leaders. A large number of private clinics and diagnostic centres were closed.

Dr Sandip Saha, a private paediatrician in the city, told Reuters he would not attend to patients except in emergencies.

Hospitals and clinics in Lucknow in Uttar Pradesh, Ahmedabad in Gujarat, Guwahati in Assam and Chennai in Tamil Nadu and other cities joined the strike, set to be one of the largest shutdowns of hospital services in recent memory.

Patients queue at hospitals

Patients queued up at hospitals, some unaware that they would not get medical attention.

“I have spent 500 rupees ($6) on travel to come here. I have paralysis and a burning sensation in my feet, head and other parts of my body,” an unidentified patient at SCB Medical College Hospital in the city of Cuttack in Odisha told local television.

“We were not aware of the strike. What can we do? We have to return home.”

Raghunath Sahu, 45, who had lined up at SCB Medical College and Hospital in Cuttack, told Reuters a daily quota set by the doctors to see patients had ended before noon.

“I have brought my ailing grandmother. They did not see her today. I will have to wait for another day and try again,” Sahu said.

India’s government introduced sweeping changes to the criminal justice system, including tougher sentences, after the 2012 Delhi gang-rape, but campaigners say little has changed and not enough has been done to deter violence against women.

“Women form the majority of our profession in this country. Time and again, we have asked for safety for them,” IMA President R. V. Asokan told Reuters on Friday.

The IMA has called for further legal measures to better protect healthcare workers from violence.