Janne-Mette Johansson, 71, told AFP that police gave her “verbal assurances” that she could take part in peaceful demonstrations against the law that critics say discriminates against India's Muslims.
“Yesterday (Thursday), Indian immigration officials came to my hotel for questioning and I was mentally tortured. Today, they again showed up at my hotel asking me to leave the country or they will take a legal action and deport me,” she said.
The woman, who had posted photos from the demonstration in the southern state of Kerala on Facebook, added that she would leave India for Dubai on Friday evening and then fly to Sweden.
European visitors to India require visas and the Press Trust of India news agency quoted an official from the Foreigners Regional Registration Office as saying that Johansson “violated visa norms”.
Earlier this week a German studying physics in the southern Indian city of Chennai was also asked to leave after taking part in a protest and comparing the law to anti-Jewish Nazi legislation, PTI reported.
Photos on social media purportedly of the student, named as Jakob Lindenthal, showed him carrying a placard saying “1933-1945 We have been there”.
“After the Nazi era, many people claimed not to have known anything about genocides or atrocities or stated that they were only passive,” Lindenthal told German broadcaster Deutsche Welle.
“Therefore I see it as a duty to learn from these lessons and not only watch when things happen that one believes to be the stepping stones to a possibly very dangerous development.”
Indian authorities have not commented on his case.
The protests, which have raged for two weeks and left at least 27 people dead, were set to continue on Friday with mobile internet snapped in places and riot police deployed.
The government says that the law easing citizenship rules for religious minorities from Bangladesh, Pakistan and Afghanistan excludes Muslims because they face no persecution in those countries.
But coupled with a mooted citizens register, it has stoked fears including in Washington and the UN rights office about the marginalisation of Muslims who make up 14 percent of India's 1.3 billion people.