Relations between India and Canada have deteriorated to the point where the countries expelled each other's top diplomats on Monday as part of their dispute about the killing of a Sikh Canadian in British Columbia.

The developments mark a near breakdown in relations, foreign policy experts and former diplomats in India told DW. 

C Raja Mohan, a visiting professor at Singapore's Institute of South Asian Studies, said the situation "will only become worse before it gets any better" and that "it will take a long time before relations get back on track."

The dispute revolves around Hardeep Singh Nijjar, a longtime campaigner for the creation of a separate homeland for Sikhs, known as Khalistan, carved out of India.

The Sikhs are a religious minority who make up 2% of India's population, with the state of Punjab as their spiritual heartland.

What did Canada say?

New Delhi viewed Nijjar as a terrorist and accused him of sponsoring attacks and killings in India.

In June 2023, he was shot dead by two masked assailants as he left a Sikh temple in Surrey, British Columbia.

Canadian authorities, including Prime Minister Justin Trudeau, have accused agents linked to the Indian government of carrying out the assassination. New Delhi has called the allegations "absurd” and "preposterous."

Canada expelled an Indian diplomat in 2023, and in response India expelled a Canadian diplomat and froze consular services for Canadians for nearly two months.

Tensions erupted again in May, when Canadian police said they had arrested three Indian citizens accused of involvement in Nijjar's killing and were "investigating if there are any ties to the government of India."

On Monday, Canada said India's top diplomat in the country was a "person of interest" in the case.

Foreign Minister Melanie Joly tied five other expelled Indian officials to Nijjar's killing and said Canada had gathered "ample, clear and concrete evidence which identified six individuals as persons of interest in the Nijjar case."

The Royal Canadian Mounted Police said they had found evidence of the involvement of Indian agents "in serious criminal activity in Canada," including links "to homicides and violent acts" and interference in Canada's democratic processes.

Indian diaspora 'the biggest sufferers'

India slammed Canada's accusations, saying Ottawa "has not shared a shred of evidence" with the government "despite many requests" from New Delhi. 

India's Foreign Ministry called the accusations part of "a deliberate strategy of smearing India for political gains." New Delhi also expelled Canada's acting high commissioner and five other diplomats.

Anil Wadhwa, a former diplomat, blamed Canada and Trudeau for the dispute.

"I do not think trade will be affected much. However, visa services will be hit and students will also feel the pinch. The hope is for sanity to prevail," he underlined.

Amitabh Mattoo, a professor of international relations at Delhi's Jawaharlal Nehru University, echoed this view.

He said "the biggest sufferers" would be the nearly 2 million members of the Indian diaspora in Canada, who make up about 5% of the country's total population.

Mattoo called on the Indian and Canadian governments to "have a serious open dialogue" on the issue.

Despite the political tensions, Raja Mohan said, trade and investment ties between the countries have not been impacted.

Raja Mohan called on the governments to "manage their actions" in such a way that there will not be "a full-blown economic fallout."

A source of tension

The row has once again put the spotlight on the Sikh separatist movement in India.

In the 1980s, during a decadelong insurgency, thousands of people were killed in Punjab. New Delhi clamped down on separatist groups to end the conflict. In 1984, at least 3,350 Sikhs were killed in a series of anti-Sikh riots in Punjab, New Delhi and elsewhere in India, according to official government figures, though Sikhs put the number far higher.   

Some in India fear a revival of militant Sikh separatism.

Canada is home to the world's largest Sikh diaspora community, with about 800,000 people, roughly 2% of the national population.

New Delhi has often complained to the Canadian government about the activities of Sikh hard-liners in the diaspora. It claims they are trying to revive the insurgency in Punjab.

The issue has long been a source of tension in India-Canada ties.

Last November, US prosecutors said an Indian official was behind a plot to assassinate a Sikh activist in New York.

New Delhi's response to that case has been notably more measured than its reaction to accusations from Canada.

Canada's domestic politics

Former Indian diplomats who spoke with DW said Trudeau's government was making accusations against India for domestic political reasons.

Ajay Bisaria, a former high commissioner to Canada, said the latest action by Ottawa was a "needless escalation by Trudeau's government of an already vexed diplomatic situation."

"Elections in Canada are due in September 2025, and the Liberals, with or without Trudeau, are expected to lose. This problem is likely to linger on until then, with political relations in freeze and low-level diplomatic representation," Bisaria said. 

"The hope is that the crisis does not escalate further, leading to bleak scenarios, like severing of diplomatic relations. On India's part, it has been treating this as a Trudeau problem rather than a Canada problem," Bisaria added.

Meera Shankar, a former Indian ambassador to the United States, offered a similar view.

"It is unfortunate that domestic politics in Canada are adversely affecting their potential geopolitical convergence with India," she said.

"India believes that Canada has been less than responsive on its concerns regarding extremist activity targeting India from their soil," she added. 

But Dal Khalsa, a pro-Khalistan organization, said its stand on Nijjar's killing had been vindicated by the Canadian government's accusations.

"For the Sikhs of Punjab, there has never been an iota of doubt that the government of India and its external intelligence agency, RAW, was the prime suspect," Kanwarpal Singh, a spokesperson for the Dal Khalsa, said in a statement.

"Time has come for the international community to hold India accountable for transnational repression," he added.

Edited by: Srinivas Mazumdaru