Famed Indian activist Sonam Wangchuk, on a hunger strike to bring autonomy to the Himalayan region of Ladakh, said on Saturday he was weak as his fast stretches into its 18th day but he would continue for three more days as planned despite pleas from supporters to stop.

Wangchuk's campaign seeks to highlight the damage to Ladakh's fragile ecology and glaciers by industrialisation as well as to protest what locals call encroachment by China.

He is determined to complete a 21-day hunger strike although supporters have urged him to end it early fearing further deterioration of his health, Wangchuk told Reuters by phone.

Even after it ends, local people and supporters will take it in turns to go on hunger strikes until he regains sufficient strength to fast again, he said.

Wangchuk added that some 2,000 people had come to his protest site in the city of Leh to show their support on Saturday. Reuters was not immediately able to confirm those numbers.

On Wednesday, thousands marched in the region's town of Kargil to demonstrate support.

After the Buddhist enclave was carved out of the Jammu and Kashmir region in 2019 by Prime Minister Narendra Modi's government, it lost what regional autonomy it had.

Modi's party promised in the 2019 national elections that Ladakh would be added to the list of states recognised under the sixth schedule of the constitution, which would allow the creation of elected local bodies to protect tribal areas, but that has yet to happen.

"Ladakh has no democracy," Wangchuk, 57, said in an earlier interview with Reuters this week, adding that if the region had elected representatives, laws could be made to protect the land and forests from industrial and mining interests.

The federal interior ministry, Ladakh Lieutenant Governor's office and Modi's Bharatiya Janata Party did not immediately respond to requests for comment.

Talks on March 4 between the federal interior ministry and regional leaders about the local demands failed.

"They have been rude and gave cold-shoulder responses," said Asgar Ali Karbalai, the co-chairman of the Kargil Democratic Alliance.

The Indian Express reported this month that the government rejected demands for Ladakh autonomy, but offered to extend protections for local jobs and land and to address other concerns.

Wangchuk said the federal government had recently "thrust" a 13-gigawatt renewable energy project on nomadic pastures in Ladakh without local consultation.

"Ladakh is like a thermometer of the planet. So if it is destroyed ... it will be a global catastrophe," he said.

Scientists have warned that glaciers in the Hindu-Kush Himalaya could lose up to 75% of their volume by the end of the century due to global warming, causing dangerous flooding and water shortages for 240 million people.

Locals and nomadic tribes will march to the border with China on April 7 to highlight what they say has been the loss of land to Chinese encroachment and corporate interests, Wangchuk said. Local shepherds allege that China has taken over some of their grazing land and earlier this year some shepherds clashed with a Chinese Army patrolling unit.

In 2018, Wangchuk received the Ramon Magsaysay Award, known as Asia's Nobel Prize, for his innovative, community-driven reforms in education for Ladakh.