Assertion: Article 370 of the Indian constitution gave special status to Jammu and Kashmir.
Reason:  Article 370 was abolished by the Jammu & Kashmir Reorganisation Act 2019 and the state was constituted into two Union Territories, viz., Jammu & Kashmir and Ladakh.

Both the Assertion and the Reason are correct but the Reason is not the correct explanation of the Assertion.

Article 370 of the Indian constitution gave special status to Jammu and Kashmir. This special status had provoked two opposite reactions. There is a section of people outside of J&K that believed that the special status of the State conferred by Article 370 did not allow full integration of the State with India. This section felt that Article 370 be revoked and J&K be treated like any other state of India. Another section, mostly Kashmiris, believe that the autonomy conferred by Article 370 is not enough.
The President’s rule was imposed in Jammu and Kashmir June 2018 after BJP withdrew its support to the Mufti government. On 5 August 2019, Article 370 was abolished by the Jammu & Kashmir Reorganisation Act 2019 and the state was constituted into two Union Territories, viz., Jammu & Kashmir and Ladakh.