Priya Pillai, a senior campaigner, was on her way to London

I was stopped at immigration, my passport stamped and told I was banned even though I have no criminal convictions pic.twitter.com/LzT3SXDbJb - priya.pillai (@PriyaPpillai) January 11, 2015

UPDATE: We have written to @HMOIndia & Airport Authority to explain the legal basis for the ban on @PriyaPpillai leaving the country. - Greenpeace India (@greenpeaceindia) January 11, 2015

Delhi airport authorities barred a Greenpeace India staff member on Sunday from flying out of India despite holding a valid visa, a move the campaign group described as "bullying" by the government.Priya Pillai, a senior campaigner, was on her way to London when immigration officials stopped her and stamped "offload" on her passport, a statement from the international environmental group said.Officials told her she was barred from leaving the country and they were "just following orders from the Indian government"."Today my right to freedom of movement has been infringed and there was an attempt to treat me like a criminal," Pillai said in the statement.The government tightened controls on foreign fund transfers to Greenpeace India in June following an intelligence report accusing activist groups of "stalling development projects" by protesting against power projects, mining and genetically modified food."The government's intentions are clear - they are trying to intimidate and bully Greenpeace and its employees," said Samit Aich, executive director of Greenpeace India."At a time when the whole world is making a strong pitch to safeguard freedom of speech and democratic rights, this action by the world's largest democracy is problematic."The Home Ministry did not immediately respond to calls for comment.Sunday's incident comes four months after another British Greenpeace staff member was stopped from entering India and put back on a London-bound flight.The government has clamped down on activist groups over the past two years following campaigns that delayed important industrial projects.Greenpeace chief Kumi Naidoo had personally appealed to Prime Minister Narendra Modi in November to release funds after the Delhi High Court directed authorities to unblock them.

Greenpeace India says it has not received any money since the order. A final hearing on the matter is expected on January 20.