Former Jammu and Kashmir Chief Minister Farooq Abdullah was detained on Monday under the Public Safety Act (PSA), which allows detention for up to two years without a trial.
The National Conference leader's house was declared as a Subsidiary jail, according to The Indian Express.
What is Public Safety Act?
The J&K Public Safety Act was introduced by the Sheikh Abdullah government and received assent from the J&K Governor on April 8, 1978.
The Act, which has often been referred to as "draconian", it allows preventive detention of people who may not have a criminal record. It was implemented by the government to prevent the smuggling of timber and keep the smugglers "out of circulation".
The United Nations High Commissioner for Human Rights had released a report in 2018, questioning the arbitrary use of PSA by the government. The report revealed that over 1,000 Kashmiris were held under the PSA between March 2016 and August 2017.
The Act was invoked widely in the aftermath of Hizbul Mujahideen commander Burhan Wani's killing in 2016, following which, hundreds of youth were detained.
In August 2018, the Act was amended to allow individuals to be detained under the PSA outside J&K as well.
The move to detain the J&K leader was made on Sunday, a day before the SC was set to hear Marumalarchi Dravida Munnetra Kazhagam (MDMK) leader Vaiko's plea, which sought Abdullah's production before the court.
The former CM had been under house arrest since August 5, when the abrogated of the special status granted to J&K through Article 370.
Union Home Minister Amit Shah had told the Parliament on August 6 that the NC leader was neither detained nor arrested. He had said that Abdullah was in J&K on his free will.
The Supreme Court on Monday issued a notice to the Centre, based on Vaiko's habeas corpus petition.
A three-judge bench, comprising of Chief Justice Ranjan Gogoi, Justice SA Bobde and Justice Abdul Nazeer, asked Solicitor General Tushar Mehta if Abdullah was under detention.
"Union home minister said Abdullah was not under any kind of detention, but we don't know his whereabouts," Vaiko's counsel said. The MDMK leader further said that Abdullah's was deprived of his constitutional rights on account of "illegal detention without any authority of law".
The bench will next hear the plea on September 30.
The SC is currently hearing petitions regarding Article 370. The bench asked Centre to ensure that normal life is restored in J&K, while also keeping national security in mind. The CJI also said that if need arises, he may visit J&K.
