A police officer confirmed that Mr Wangchuk and all other 'padayatris' were released in the evening.
Climate activist Sonam Wangchuk and several others from Ladakh paid tributes to Mahatma Gandhi at his memorial Rajghat on Wednesday evening and later said they have been released from police detention and ended their fast.
The group gave a memorandum to the government listing their demands, and have been assured of a meeting with top leadership soon, Mr Wangchuk said, adding they have ended their fast.
"We have given a memorandum to the government to protect Ladakh under such constitutional provisions so that its ecology can be preserved, in this case it is the Sixth Schedule, which gives locals the right to govern and manage the resources," Mr Wangchuk told media after visiting Mahatma Gandhi's memorial.
"Locals should be empowered in the Himalayas because they can best preserve it," he said.
"In the coming days, we will meet the prime minister, president or home minister, this is the assurance we have been given by the home ministry," he said.
"We have demanded a democratic set-up for Ladakh, and the Sixth Schedule is also a part of it. We have been assured that we will meet top leadership, and the date of meeting will be confirmed in a couple of days," Mr Wangchuk said.
A senior police officer confirmed that Mr Wangchuk and all other 'padayatris' were released in the evening.
"They were allowed to go after an assurance from them of not gathering or holding any yatra as Section 163 is imposed in central parts of the national capital," the officer said.
Sonam Wangchuk was kept at the Bawana police station while other 'padayatris' were at three other police stations at Delhi-Haryana border.
All were escorted in buses by police personnel till Rajghat at about 9.30 pm and later, Mr Wangchuk and all others 'padayatris' were allowed to go.
Police sources said Mr Wangchuk might stay in Delhi for a few more days to seek meeting with the government.
Mr Wangchuk said they have been assured that talks with the representatives of the Leh Apex Body and Kargil Democratic Alliance will resume within 15 days.
Mr Wangchuk was leading the 'Delhi Chalo Padyatra', which began from Leh a month ago. Around 170 people from Ladakh, who were marching to Delhi demanding safeguards under the Sixth Schedule of the Constitution for the Union Territory among other things, were detained on Monday night at Delhi's Singhu border, and were taken to different police stations where they went on a hunger strike.
The march was organised by the Leh Apex Body (LAB), which along with the Kargil Democratic Alliance (KDA), has been spearheading an agitation for the past four years to demand statehood for Ladakh, seek its inclusion under the Sixth Schedule of the Constitution, early recruitment process along with a public service commission for Ladakh and separate Lok Sabha seats for Leh and Kargil districts.
Delhi Police had detained them citing the imposition of section 163 (which was earlier section 144 of CrPC) of Bharatiya Nagarik Suraksha Sanhita in the districts of New Delhi, North and Central and all police stations jurisdiction sharing the borders with other states.
(Except for the headline, this story has not been edited by NDTV staff and is published from a syndicated feed.)