The airlines, including Emirates, Air Canada and Qatar Airways, suspended flights after Pakistan closed its airspace. Flight trackers showed that some even had to turn back mid-route.
Later on Wednesday, airlines began restarting their services, but on alternate routes.
WATCH: India and Pakistan on the brink of all-out military conflict
Air Canada explained in an email to Global News that all flights to India were temporarily cancelled after one en route to Delhi was forced to turn back to Toronto.
The airline said its Toronto to Mumbai flight will operate on time Wednesday night, but on a different route.
Due to a lack of suitable alternative routes to Delhi, Air Canada said it has cancelled its Wednesday night flights from Toronto and Vancouver.
WATCH: B.C. flights to India and Pakistan cancelled over unrest concerns
“We continue to monitor this situation closely and flights to Delhi will operate as soon as operationally feasible,” the airline said in an emailed statement.
Air Canada has enacted its goodwill policy for customers affected by cancellations.
The airline operates a daily service from Toronto and Vancouver to Delhi, and has a four-times-weekly flight from Toronto to Mumbai. It does not fly to Pakistan.
Pakistan International Airlines posted on Twitter Wednesday that travellers should “expect delays.”
Air India also tweeted that it is planning to reroute some of its flights to try and minimize delays.
India-based airline Jet Airways urged passengers to check their flight’s status to see if it is affected. It noted that several flights are taking alternate routes and will not be delayed. Customers on affected flights will not be charged penalties.
The Canadian government also is urging caution for those travelling to certain parts of India and Pakistan.
The government is advising Canadians to avoid all non-essential travel to Pakistan, saying the “security situation is unpredictable.”
WATCH: Indian air force helicopter crashes in Kashmir
“There is a threat of terrorist attacks, kidnapping and sectarian violence,” the advisory reads.
The government has a more stern advisory for certain parts of Pakistan, where its says to avoid all travel.
Those areas include:
For India, the government has issued regional advisories.
It notes that Canadians travelling to India should “exercise a high degree of caution” due to the threat of terror attacks throughout the country.
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Regionally, it says to avoid all travel to Jammu and Kashmir. It also says to avoid all travel within 10 kilometres of the country’s border with Pakistan in the states of Gujarat, Punjab and Rajastan.
The border advisory is “due to the possibility of landmines and unexploded ordnance,” the government explains.
The Wagah border crossing and towns farther from the border, such as Amritsar in Punjab and Bikaner and Jaisalmer in Rajasthan, are not included in the advisory.
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Canada also has other travel advisories for northeastern India, and relating to its shared border with Bangladesh and Myanmar.
Other countries, such as the United Kingdom and New Zealand have also issued travel warnings for India and Pakistan this week.
The latest wave of tensions between Pakistan and India first erupted after the militant group Jaish-e-Mohammad claimed responsibility for a Feb. 14 suicide bombing that killed over 40 Indian troops travelling in a convoy of paramilitary forces in the Indian portion of Kashmir.
Pakistan has said it was not involved in the attack and was ready to help New Delhi in the investigations. India has long accused Pakistan of cultivating such militant groups to attack it.
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