India has told Canada that it must repatriate 41 diplomats by Oct 10, the Financial Times reported on Tuesday.
Ties between India and Canada have become seriously strained over Canadian suspicion that Indian government agents had a role in the June murder in Canada of a Sikh separatist leader and Canadian citizen, Hardeep Singh Nijjar, who India had labelled a "terrorist".
India has dismissed the allegation as absurd.
The Financial Times, citing people familiar with the Indian demand, said India had threatened to revoke the diplomatic immunity of those diplomats told to leave who remained after Oct 10.
Canada has 62 diplomats in India and India had said that the total should be reduced by 41, the newspaper said.
The Indian and Canadian foreign ministries did not immediately respond to requests for comment.
Indian Foreign Minister Subrahmanyam Jaishankar said earlier there was a "climate of violence" and an "atmosphere of intimidation" against Indian diplomats in Canada, where the presence of Sikh separatist groups has frustrated New Delhi.