Haridwar: Environmentalist G D Agrawal was arrested by police at Har-ki-Pauri here when he was about to leave for examining water of Ganga.
Agrawal, who is also known as Swami Gyan Swaroop Sanand, was later taken to the PWD guest house at nearby Roorkee town where he began his fast.
The environmentalist had yesterday announced that he would go to Srinagar in Garhwal to examine the quality of Ganga water, which he said, is deteriorating due to the construction of dams.
Agarwal had threatened to undertake a fast if the administration tried to stop him from going.
He claimed that 90 percent of the useful elements of the Ganga water are destroyed due to the storage of Ganga water for Tehri dam.
"So, I want to go to Srinagar to check the quality of water and then put the facts before the Prime Minister."
On resumption of work on the near-completed 330 MW Alaknanda project, the former IIT professor threatened to drown himself in Ganga.
As locals and supporters of hydroelectric projects are agitating over the resumption of work, police arrested Agrawal to avoid any untoward incident.