Faesal, who was bound for Istanbul, was detained at the airport on Wednesday morning, they said.
The former bureaucrat from Jammu and Kashmir had floated a political outfit after resigning from the Indian Administrative Service (IAS).
After being detained at the Delhi airport, he was again detained under the PSA on his arrival in Srinagar, officials said.
Post the removal of special status to Jammu and Kashmir, provided under Article 370, Faesal had said Kashmir is experiencing an "unprecedented" lockdown and its eight million population "incarcerated" like never before.
He is the president of the J&K Peoples Movement party.