Article 370 is sensitive because it guarantees significant autonomy for the Muslim-majority state.
The measure was accompanied by a telecoms and media blackout which began on Sunday evening.
There is a long-running insurgency on the Indian side. India and Pakistan fought several conflicts over Kashmir.
For many Kashmiris, Article 370 was the main justification for being a part of India and by revoking it, the BJP has irrevocably changed Delhi’s relationship with the region, the BBC’s Geeta Pandey reports from Delhi.
Meanwhile India’s parliament is expected to pass a bill splitting Indian-administered Kashmir into two territories governed directly by Delhi.
Pakistan condemned India’s decision to revoke the special status of its part of Kashmir as illegal, saying it would “exercise all possible options” to counter it.
“India is playing a dangerous game which will have serious consequences for regional peace and stability,” said Foreign Minister Shah Mehmood Qureshi.
But an Indian government source said there was no external implication as the Line of Control, the de facto border, and boundaries of Kashmir had not been altered.
Why are there tensions over Kashmir?
During the partition of the Indian subcontinent in 1947, some expected Jammu and Kashmir, like other Muslim-majority regions, to go to Pakistan.
But the ruler of the princely state, who had initially wanted Jammu and Kashmir to become independent, joined India in return for help against an invasion of tribesmen from Pakistan.
War broke out between India and Pakistan, and Kashmir effectively became partitioned.
The region, which remains one of the most militarised zones in the world, has been a flashpoint between India and Pakistan for more than six decades.
By the time we woke up this morning, the internet was gone and we now have no mobile connectivity.
If people step out of their homes, they see paramilitary forces on every street. Almost every major road is shut – we are hearing that more troops are being deployed.
No-one knows what is happening in other parts of the state – we can’t talk to anyone else.
People are concerned – they don’t know what is happening, they don’t know what is going to happen.
It’s an atmosphere of fear. People are scared to come out, they have stockpiled food for months.
Kashmiris have always been willing to defend the state’s special status. It looks like a long road ahead, and no-one knows what’s next.