Other religions comprise less than 1% each, including 819 adherents of Judaism. Indian immigrants introduced Hinduism to Norway, which in 2011 has slightly more than 5,900 adherents, or 1% of non-Lutheran Norwegians. Sikhism has approximately 3,000 adherents, with most living in Oslo, which has two gurdwaras. Sikhs first came to Norway in the early 1970s. The troubles in Punjab after Operation Blue Star and riots committed against Sikhs in India after the assassination of Indira Gandhi led to an increase in Sikh refugees moving to Norway. Drammen also has a sizeable population of Sikhs; the largest gurdwara in north Europe was built in Lier. There are eleven Buddhist organisations, grouped under the Buddhistforbundet organisation, with slightly over 14,000 members, which make up 0.2% of the population. The Baháʼí Faith religion has slightly more than 1,000 adherents. Around 1.7% (84,500) of Norwegians belong to the secular Norwegian Humanist Association.