Andy Pag was ordered by a court in western India to pay a fine of 1,000 rupees ($20) for violating Indian wireless and telegraphy laws, his lawyer Prateek Kasliwal said.
India has strict laws governing the use of satellite phones, especially in its border states, to curb their use by terror groups.
The court dropped a more serious charge related to misuse of the satellite phone for espionage and terrorist activity.
Pag, a 35-year-old dual Italian and British citizen whose full name is Andrea Pagnacco, was arrested in the town of Pushkar in Rajasthan state in January after Indian army radars detected his satellite phone. He was granted bail a week later but was ordered to remain in the country while the charges were investigated.
Pag told the court he was unaware that he needed to get a permit to use a satellite phone in India.
“I am a very relieved person after having suffered for 69 long days,” Pag said. “I am happy that the court found me innocent, and that I was not using the satellite phone for any terrorist activities.”
The activist said he would travel to Nepal before returning to London.
Pag left London in September in a bus converted to run on vegetable oil and was chronicling his journey in a blog.
He has previously driven from London to Timbuktu in a chocolate-fueled truck and organized a London to Athens rally for biofuel vehicles called Grease to Greece.
