The army has been called into north-eastern India, after thousands of people defied curfews to protest against a new citizenship bill.
The Citizenship Amendment Bill offers amnesty to non-Muslim illegal immigrants from Afghanistan, Pakistan and Bangladesh.
Critics say the bill discriminates against Muslims - but in the north-east, protesters claim they will be "overrun" by Hindus from Bangladesh.
Officials said 20-30 people were injured in the demonstrations, and air and railway services have been severely impacted.
Railway services have been suspended, with some reports suggesting that at least two railway stations have been burned down, and some airlines have started offering rescheduling or cancellation fee waivers.
Following the protests, Indian Prime Minister Narendra Modi has appealed for calm, as he attempted to reassure people in Assam, telling them they had "nothing to worry" about.