The period from 1917 to 1946 marked the darkest chapter in South Asian American history, characterized by systematic legal exclusion and discrimination. The Immigration Act of 1917, also known as the Asiatic Barred Zone Act, prohibited immigration from most of Asia, including the Indian subcontinent.

This legislation created an "Asiatic Barred Zone" that excluded people from a vast geographic area stretching from Arabia to Southeast Asia. The law effectively ended the modest flow of South Asian immigration that had begun in the early 1900s, separating families and isolating the small community already in America.

The situation worsened with the 1923 Supreme Court decision in United States v. Bhagat Singh Thind, which ruled that Indians, though scientifically classified as Caucasian, were not "white" in the common understanding and therefore ineligible for citizenship. This decision led to the denaturalization of dozens of Indian Americans who had previously obtained citizenship.

Without citizenship rights, South Asians couldn't vote, own land in many states, or bring family members to America. Many were forced to return to India, while those who remained faced severe social and economic marginalization. The community shrank from about 6,000 in 1920 to fewer than 2,500 by 1940.

The exclusion era finally ended with the Luce-Celler Act of 1946, which allowed a token quota of 100 Indians per year to immigrate and made them eligible for citizenship. Though minimal, this represented the first crack in the wall of exclusion that had isolated the community for nearly three decades.